C.8 Modality Specific Modules

C.8.1 Computed Radiography Modules

This Section describes Computed Radiography Series and Image Modules. These Modules contain Attributes that are specific to Computed Radiography images. There is no Computed Radiography Equipment Module.

C.8.1.1 CR Series Module

Table C.8-1 contains IOD Attributes that describe a computed radiography series performed on the patient.

Table C.8-1. CR Series Module Attributes

Attribute Name

Tag

Type

Attribute Description

Body Part Examined

(0018,0015)

2

Text description of the part of the body examined. See Annex L “Correspondence of Anatomic Region Codes and Body Part Examined Defined Terms” in PS3.16 for Defined Terms

View Position

(0018,5101)

2

Radiographic view associated with Patient Position (0018,5100).

For humans:

Defined Terms:

AP

Anterior/Posterior

PA

Posterior/Anterior

LL

Left Lateral

RL

Right Lateral

RLD

Right Lateral Decubitus

LLD

Left Lateral Decubitus

RLO

Right Lateral Oblique

LLO

Left Lateral Oblique

For animals, capitalized versions with hyphens replaced by underscores of the abbreviations defined in "Smallwood et al. A Nomenclature for Radiographic Projections Used In Veterinary Medicine" shall be used. See CID 7484 “DX View for Animals”, in which these abbreviations are listed.

Note

  1. For example, the Defined Term "CD10DI_CRPRO" would be used for a "Cd10Di-CrPrO" or "caudal 10-degree distal-cranioproximal oblique".

  2. The Code String value representation for this attribute constrains the characters to uppercase, digits and underscore.

Filter Type

(0018,1160)

3

Label for the type of filter inserted into the x-ray beam

Collimator/grid Name

(0018,1180)

3

Label describing any grid inserted.

Focal Spot(s)

(0018,1190)

3

Size of the focal spot in mm. For devices with variable focal spot or multiple focal spots, small dimension followed by large dimension.

Plate Type

(0018,1260)

3

Label of the type of storage phosphor plates used in this series

Phosphor Type

(0018,1261)

3

Label of type of phosphor on the plates


C.8.1.2 CR Image Module

Table C.8-2 contains IOD Attributes that describe computed radiography images.

Table C.8-2. CR Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data.

Enumerated Values:

MONOCHROME1

MONOCHROME2

KVP

(0018,0060)

3

Peak kilo voltage output of the x-ray generator used

Plate ID

(0018,1004)

3

The ID or serial number of the sensing plate upon which the image was acquired

Distance Source to Detector

(0018,1110)

3

Distance in mm from source to detector center.

Note

This value is traditionally referred to as Source Image Receptor Distance (SID).

Distance Source to Patient

(0018,1111)

3

Distance in mm from source to center of field of view.

Note

This value is traditionally referred to as Source Object Distance (SOD).

Exposure Time

(0018,1150)

3

Time of x-ray exposure in msec

X-Ray Tube Current

(0018,1151)

3

X-Ray Tube Current in mA.

Exposure

(0018,1152)

3

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current.

Exposure in µAs

(0018,1153)

3

The exposure expressed in µAs, for example calculated from Exposure Time and X-Ray Tube Current.

Imager Pixel Spacing

(0018,1164)

3

Physical distance measured at the front plane of the Image Receptor housing between the center of each pixel. Specified by a numeric pair - row spacing value (delimiter) column spacing value - in mm.

In the case of CR, the front plane is defined to be the external surface of the CR plate closest to the patient and radiation source.

Include Table 10-10 “Basic Pixel Spacing Calibration Macro Attributes”

Generator Power

(0018,1170)

3

Power in kW to the x-ray generator.

Acquisition Device Processing Description

(0018,1400)

3

Describes device-specific processing associated with the image (e.g., Organ Description)

Acquisition Device Processing Code

(0018,1401)

3

Code representing the device-specific processing associated with the image (e.g., CR Organ Filtering code)

Cassette Orientation

(0018,1402)

3

Orientation of cassette, used to properly position the image for display.

Enumerated Values:

LANDSCAPE

PORTRAIT

Cassette Size

(0018,1403)

3

Size of cassette.

Defined Terms:

18CMX24CM

8INX10IN

24CMX30CM

10INX12IN

30CMX35CM

30CMX40CM

11INX14IN

35CMX35CM

14INX14IN

35CMX43CM

14INX17IN

Exposures on Plate

(0018,1404)

3

Total number of x-ray exposures that have been made on the plate identified in Plate ID (0018,1004)

Relative X-Ray Exposure

(0018,1405)

3

Relative x-ray exposure on the plate. Meaning of values is implementation specific. May be used to adjust the dynamic range of the plate digitizer (scanner).

Note

This value is manufacturer-specific. DICOM specifies standard Attributes in Table 10-23 “Exposure Index Macro Attributes”, which are recommended.

Sensitivity

(0018,6000)

3

Read out sensitivity.

Note

This value is manufacturer-specific. DICOM specifies standard Attributes in Table 10-23 'Exposure Index Macro', which are recommended.

Include Table 10-7 “General Anatomy Optional Macro Attributes”

Defined CID for the Anatomic Region Sequence is 4009 for humans, and 7482 for animals.

Include Table 10-23 “Exposure Index Macro Attributes”


C.8.2 CT Modules

This Section describes the CT Image Module. This Module contains all Attributes that are specific to CT images.

C.8.2.1 CT Image Module

The table in this Section contains IOD Attributes that describe CT images.

Table C.8-3. CT Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Image Type

(0008,0008)

1

Image identification characteristics. See Section C.8.2.1.1.1 for specialization.

Samples per Pixel

(0028,0002)

1

Number of samples (planes) in this image. See Section C.8.2.1.1.2 for specialization.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data. See Section C.8.2.1.1.3 for specialization.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See Section C.8.2.1.1.4 for specialization.

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample. Each sample shall have the same number of bits stored. See Section C.8.2.1.1.5 for specialization.

High Bit

(0028,0102)

1

Most significant bit for pixel sample data. Each sample shall have the same high bit. See Section C.8.2.1.1.6 for specialization.

Rescale Intercept

(0028,1052)

1

The value b in relationship between stored values (SV) and the output units.

Output units = m*SV+b

If Image Type (0008,0008) Value 1 is ORIGINAL and Value 3 is not LOCALIZER, output units shall be Hounsfield Units (HU).

Rescale Slope

(0028,1053)

1

m in the equation specified in Rescale Intercept (0028,1052).

Rescale Type

(0028,1054)

1C

Specifies the output units of Rescale Slope (0028,1053) and Rescale Intercept (0028,1052).

See Section C.11.1.1.2 for Defined Terms and further explanation.

Required if the Rescale Type is not HU (Hounsfield Units). May be present otherwise.

KVP

(0018,0060)

2

Peak kilo voltage output of the x-ray generator used

Acquisition Number

(0020,0012)

2

A number identifying the single continuous gathering of data over a period of time that resulted in this image

Scan Options

(0018,0022)

3

Parameters of scanning sequence.

Data Collection Diameter

(0018,0090)

3

The diameter in mm of the region over which data were collected

Data Collection Center (Patient)

(0018,9313)

3

The x, y, and z coordinates (in the patient coordinate system) in mm of the center of the region in which data were collected. See Section C.8.15.3.6.1.

Reconstruction Diameter

(0018,1100)

3

Diameter in mm of the region from within which data were used in creating the reconstruction of the image. Data may exist outside this region and portions of the patient may exist outside this region.

Reconstruction Target Center (Patient)

(0018,9318)

3

The x, y, and z coordinates (in the patient coordinate system) of the reconstruction center target point as used for reconstruction in mm. See Section C.8.15.3.6.1.

Note

If the reconstructed image is not magnified or panned the value corresponds with the Data Collection Center (Patient) (0018,9313) attribute.

Distance Source to Detector

(0018,1110)

3

Distance in mm from source to detector center.

Note

This value is traditionally referred to as Source Image Receptor Distance (SID).

Distance Source to Patient

(0018,1111)

3

Distance in mm from source to isocenter (center of field of view).

Note

This value is traditionally referred to as Source Object Distance (SOD).

Gantry/Detector Tilt

(0018,1120)

3

Nominal angle of tilt in degrees of the scanning gantry. Not intended for mathematical computations.

Table Height

(0018,1130)

3

The distance in mm of the top of the patient table to the center of rotation; below the center is positive.

Rotation Direction

(0018,1140)

3

Direction of rotation of the source when relevant, about nearest principal axis of equipment.

Enumerated Values:

CW

clockwise

CC

counter clockwise

Exposure Time

(0018,1150)

3

Time of x-ray exposure in msec.

If Acquisition Type (0018,9302) equals SPIRAL, the value of this attribute shall be Revolution Time (0018,9305) divided by the Spiral Pitch Factor (0018,9311). See Section C.8.15.3.8.1 and Section C.8.15.3.2.1.

X-Ray Tube Current

(0018,1151)

3

X-Ray Tube Current in mA.

Exposure

(0018,1152)

3

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current.

Exposure in µAs

(0018,1153)

3

The exposure expressed in µAs, for example calculated from Exposure Time and X-Ray Tube Current.

Filter Type

(0018,1160)

3

Label for the type of filter inserted into the x-ray beam.

Generator Power

(0018,1170)

3

Power in kW to the x-ray generator.

Focal Spot(s)

(0018,1190)

3

Size of the focal spot in mm. For devices with variable focal spot or multiple focal spots, small dimension followed by large dimension.

Convolution Kernel

(0018,1210)

3

A label describing the convolution kernel or algorithm used to reconstruct the data

Revolution Time

(0018,9305)

3

The time in seconds of a complete revolution of the source around the gantry orbit.

Single Collimation Width

(0018,9306)

3

The width of a single row of acquired data (in mm).

Note

Adjacent physical detector rows may have been combined to form a single effective acquisition row.

Total Collimation Width

(0018,9307)

3

The width of the total collimation (in mm) over the area of active x-ray detection.

Note

This will be equal the number of effective detector rows multiplied by single collimation width.

Table Speed

(0018,9309)

3

The distance in mm that the table moves in one second during the gathering of data that resulted in this image.

Table Feed per Rotation

(0018,9310)

3

Motion of the table (in mm) during a complete revolution of the source around the gantry orbit.

Spiral Pitch Factor

(0018,9311)

3

Ratio of the Table Feed per Rotation (0018,9310) to the Total Collimation Width (0018,9307).

Exposure Modulation Type

(0018,9323)

3

A label describing the type of exposure modulation used for the purpose of limiting the dose.

Defined Terms:

NONE

Estimated Dose Saving

(0018,9324)

3

A percent value of dose saving due to the use of Exposure Modulation Type (0018,9323). A negative percent value of dose savings reflects an increase of exposure.

CTDIvol

(0018,9345)

3

Computed Tomography Dose Index (CTDIvol), in mGy according to IEC 60601-2-44, Ed.2.1 (Clause 29.1.103.4), The Volume CTDIvol. It describes the average dose for this image for the selected CT conditions of operation.

CTDI Phantom Type Code Sequence

(0018,9346)

3

The type of phantom used for CTDI measurement according to IEC 60601-2-44.

Only a single Item is permitted in this Sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

Defined CID 4052 “Phantom Devices”.

Include Table 10-7 “General Anatomy Optional Macro Attributes”

Defined CID for the Anatomic Region Sequence is CID 4030 “CT, MR and PET Anatomy Imaged”.

Include Table 10-25 “Optional View and Slice Progression Direction Attributes”

Calcium Scoring Mass Factor Patient

(0018,9351)

3

The calibration factor for the calcium mass score. These factors incorporate the effects of

  • KV value of the CT image

  • the patient size.

  • machine specific corrections

See Section C.8.2.1.1.7.

Calcium Scoring Mass Factor Device

(0018,9352)

3

The calibration factors for the calcium mass score of the device. These factors incorporate the effects of

  • KV value of the CT image

  • machine specific corrections

This a multi-value attribute, the first value specifies the mass factor for a small patient size, the second value for a medium patient size and the third value for a large patient size.

See Section C.8.2.1.1.7.

Energy Weighting Factor

(0018,9353)

1C

The weighting factor of the data from the primary source in a multiple energy composition image. This factor incorporates the effects of

  • the specific X-Ray source and kV value

  • examination specific characteristics.

Required if one Derivation Code Sequence (0008,9215) Item value is (113097, DCM, "Multi-energy proportional weighting"). May be present otherwise.

CT Additional X-Ray Source Sequence

(0018,9360)

3

Contains the attributes describing additional acquisition parameters beyond the primary source in a multiple X-Ray source system or a multi-energy acquisition. The primary X-Ray source is specified in other attributes of this module.

One or more Items are permitted in this sequence.

>KVP

(0018,0060)

1

Peak kilo voltage output of the X-Ray generator used.

>X-Ray Tube Current in mA

(0018,9330)

1

Nominal X-Ray tube current in milliamperes.

>Data Collection Diameter

(0018,0090)

1

The diameter in mm of the region over which data were collected.

>Focal Spot(s)

(0018,1190)

1

Used nominal size of the focal spot in mm.

>Filter Type

(0018,1160)

1

Type of filter(s) inserted into the X-Ray beam.

>Filter Material

(0018,7050)

1

The X-Ray absorbing material used in the filter.

>Exposure in mAs

(0018,9332)

3

The exposure expressed in milliampere seconds, for example calculated from exposure time and X-Ray tube current.

>Energy Weighting Factor

(0018,9353)

1C

The weighting factor of the data from this additional source in a multiple energy composition image. This factor incorporates the effects of

  • the specific X-Ray source and kV value

  • examination specific characteristics.

Required if one Derivation Code Sequence (0008,9215) Item value is (113097, DCM, "Multi-energy proportional weighting"). May be present otherwise.

Isocenter Position

(300A,012C)

3

Isocenter coordinates (x,y,z), in mm. Specifies the location of the machine isocenter in the patient-based coordinate system associated with the Frame of Reference. It allows transformation from the equipment-based coordinate system to the patient-based coordinate system.

Include Table 10-27 “RT Equipment Correlation Macro Attributes Description”


C.8.2.1.1 CT Image Attribute Descriptions
C.8.2.1.1.1 Image Type

For CT Images, Image Type (0008,0008) is specified to be Type 1.

Defined Terms for Value 3:

AXIAL

identifies a CT Axial Image

LOCALIZER

dentifies a CT Localizer Image

Note

Axial in this context means any cross-sectional image, and includes transverse, coronal, sagittal and oblique images.

C.8.2.1.1.2 Samples Per Pixel

Enumerated Values:

1

C.8.2.1.1.3 Photometric Interpretation

Enumerated Values:

MONOCHROME1

MONOCHROME2

See Section C.7.6.3.1.2 for definition of these terms.

C.8.2.1.1.4 Bits Allocated

Enumerated Values:

16

C.8.2.1.1.5 Bits Stored

Enumerated Values:

12

13

14

15

16

C.8.2.1.1.6 High Bit

For CT Images, High Bit (0028,0102) shall have be one less than the value sent in Bits Stored.

C.8.2.1.1.7 Calcium Scoring Mass Factor Patient and Device

The calibration factors for the Calcium Scoring Mass Factor Patient (0018,9351) and Calcium Scoring Mass Factor Device (0018,9352) attributes are defined by the International Consortium for Multi-Detector CT Evaluation of Coronary Calcium, see McCollough, C.H. "A multi-institutional, multi-manufacturer, international standard for the quantification of coronary artery calcium using cardiac CT".

C.8.3 MR Modules

This Section describes the MR Image Module. This Module contains all Attributes that are specific to MR images.

C.8.3.1 MR Image Module

Table C.8-4 contains the Attributes that describe MR images.

Table C.8-4. MR Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Image Type

(0008,0008)

1

Image identification characteristics. See Section C.8.3.1.1.1 for specialization.

Samples per Pixel

(0028,0002)

1

Number of samples (planes) in this image. See Section C.8.3.1.1.2 for specialization.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data. See Section C.8.3.1.1.3 for specialization.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See Section C.8.3.1.1.4 for specialization.

Scanning Sequence

(0018,0020)

1

Description of the type of data taken.

Enumerated Values:

SE

Spin Echo

IR

Inversion Recovery

GR

Gradient Recalled

EP

Echo Planar

RM

Research Mode

Note

Multi-valued, but not all combinations are valid (e.g., SE/GR, etc.).

Sequence Variant

(0018,0021)

1

Variant of the Scanning Sequence.

Defined Terms:

SK

segmented k-space

MTC

magnetization transfer contrast

SS

steady state

TRSS

time reversed steady state

SP

spoiled

MP

MAG prepared

OSP

oversampling phase

NONE

no sequence variant

Scan Options

(0018,0022)

2

Parameters of scanning sequence.

Defined Terms:

PER

Phase Encode Reordering

RG

Respiratory Gating

CG

Cardiac Gating

PPG

Peripheral Pulse Gating

FC

Flow Compensation

PFF

Partial Fourier - Frequency

PFP

Partial Fourier - Phase

SP

Spatial Presaturation

FS

Fat Saturation

MR Acquisition Type

(0018,0023)

2

Identification of data encoding scheme.

Enumerated Values:

2D

frequency x phase

3D

frequency x phase x phase

Repetition Time

(0018,0080)

2C

The period of time in msec between the beginning of a pulse sequence and the beginning of the succeeding (essentially identical) pulse sequence. Required except when Scanning Sequence (0018,0020) is EP and Sequence Variant (0018,0021) is not SK.

Echo Time

(0018,0081)

2

Time in ms between the middle of the excitation pulse and the peak of the echo produced (kx=0). In the case of segmented k-space, the TE(eff) is the time between the middle of the excitation pulse to the peak of the echo that is used to cover the center of k-space (i.e.,-kx=0, ky=0).

Echo Train Length

(0018,0091)

2

Number of lines in k-space acquired per excitation per image.

Inversion Time

(0018,0082)

2C

Time in msec after the middle of inverting RF pulse to middle of excitation pulse to detect the amount of longitudinal magnetization. Required if Scanning Sequence (0018,0020) has values of IR.

Trigger Time

(0018,1060)

2C

Time, in msec, between peak of the R wave and the peak of the echo produced. In the case of segmented k-space, the TE(eff) is the time between the peak of the echo that is used to cover the center of k-space. Required for Scan Options (0018,0022) that include heart gating (e.g., CG, PPG, etc.)

Sequence Name

(0018,0024)

3

User defined name for the combination of Scanning Sequence (0018,0020) and Sequence Variant (0018,0021).

Angio Flag

(0018,0025)

3

Angio Image Indicator. Primary image for Angio processing.

Enumerated Values:

Y

Image is Angio

N

Image is not Angio

Number of Averages

(0018,0083)

3

Number of times a given pulse sequence is repeated before any parameter is changed

Imaging Frequency

(0018,0084)

3

Precession frequency in MHz of the nucleus being addressed

Imaged Nucleus

(0018,0085)

3

Nucleus that is resonant at the imaging frequency. Examples: 31P, 1H

Echo Number(s)

(0018,0086)

3

The echo number used in generating this image. In the case of segmented k-space, it is the effective Echo Number.

Magnetic Field Strength

(0018,0087)

3

Nominal field strength of MR magnet, in Tesla

Spacing Between Slices

(0018,0088)

3

Spacing between slices, in mm. The spacing is measured from the center-to-center of each slice.

Number of Phase Encoding Steps

(0018,0089)

3

Total number of lines in k-space in the 'y' direction collected during acquisition.

Percent Sampling

(0018,0093)

3

Fraction of acquisition matrix lines acquired, expressed as a percent.

Percent Phase Field of View

(0018,0094)

3

Ratio of field of view dimension in phase direction to field of view dimension in frequency direction, expressed as a percent.

Pixel Bandwidth

(0018,0095)

3

Reciprocal of the total sampling period, in hertz per pixel.

Nominal Interval

(0018,1062)

3

Average R-R interval used for the scans, in msec

Beat Rejection Flag

(0018,1080)

3

Beat length sorting has been applied.

Enumerated Values:

Y

yes

N

no

Low R-R Value

(0018,1081)

3

R-R interval low limit for beat rejection, in msec

High R-R Value

(0018,1082)

3

R-R interval high limit for beat rejection, in msec

Intervals Acquired

(0018,1083)

3

Number of R-R intervals acquired.

Intervals Rejected

(0018,1084)

3

Number of R-R intervals rejected.

PVC Rejection

(0018,1085)

3

Description of type of PVC rejection criteria used.

Skip Beats

(0018,1086)

3

Number of beats skipped after a detected arrhythmia.

Heart Rate

(0018,1088)

3

Beats per minute.

Cardiac Number of Images

(0018,1090)

3

Number of images per cardiac cycle.

Trigger Window

(0018,1094)

3

Percent of R-R interval, based on Heart Rate (0018,1088), prescribed as a window for a valid/usable trigger.

Reconstruction Diameter

(0018,1100)

3

Diameter in mm. of the region from within which data were used in creating the reconstruction of the image. Data may exist outside this region and portions of the patient may exist outside this region.

Receive Coil Name

(0018,1250)

3

Receive coil used.

Transmit Coil Name

(0018,1251)

3

Transmit coil used.

Acquisition Matrix

(0018,1310)

3

Dimensions of the acquired frequency /phase data before reconstruction.

Multi-valued: frequency rows\frequency columns\phase rows\phase columns.

In-plane Phase Encoding Direction

(0018,1312)

3

The axis of phase encoding with respect to the image.

Enumerated Values:

ROW

phase encoded in rows.

COL

phase encoded in columns.

Flip Angle

(0018,1314)

3

Steady state angle in degrees to which the magnetic vector is flipped from the magnetic vector of the primary field.

SAR

(0018,1316)

3

Calculated whole body Specific Absorption Rate in watts/kilogram.

Variable Flip Angle Flag

(0018,1315)

3

Flip angle variation applied during image acquisition.

Enumerated Values:

Y

yes

N

no

dB/dt

(0018,1318)

3

The rate of change of the gradient coil magnetic flux density with time (T/s).

Temporal Position Identifier

(0020,0100)

3

Temporal order of a dynamic or functional set of Images.

Number of Temporal Positions

(0020,0105)

3

Total number of temporal positions prescribed.

Temporal Resolution

(0020,0110)

3

Time delta between Images in a dynamic or functional set of Images.

Include Table 10-7 “General Anatomy Optional Macro Attributes”

Defined CID for the Anatomic Region Sequence is 4030.

Include Table 10-25 “Optional View and Slice Progression Direction Attributes”

Isocenter Position

(300A,012C)

3

Isocenter coordinates (x,y,z), in mm. Specifies the location of the machine isocenter in the patient-based coordinate system associated with the Frame of Reference. It allows transformation from the equipment-based coordinate system to the patient-based coordinate system.


C.8.3.1.1 MR Image Attribute Descriptions
C.8.3.1.1.1 Image Type

For MR Images, Image Type (0008,0008) is specified to be Type 1.

Defined Terms for Value 3:

DENSITY MAP

DIFFUSION MAP

IMAGE ADDITION

MODULUS SUBTRACT

MPR

OTHER

PHASE MAP

PHASE SUBTRACT

PROJECTION IMAGE

T1 MAP

T2 MAP

VELOCITY MAP

C.8.3.1.1.2 Samples Per Pixel

Enumerated Values:

1

C.8.3.1.1.3 Photometric Interpretation

Enumerated Values:

MONOCHROME1

MONOCHROME2

See Section C.7.6.3.1.2 for definition of these terms.

C.8.3.1.1.4 Bits Allocated

Enumerated Values:

16

C.8.4 Nuclear Medicine Modules

This Section describes Nuclear Medicine Series, Equipment, and Image Modules. These Modules contain Attributes that are specific to the NM Image IOD.

Note

There are some cases where it may be necessary to use several SOP Instances to encode a single NM acquisition. For example, the matrix size must remain constant within a SOP instance. Multiple matrix sizes require multiple SOP instances. Similarly, multiple gated stress levels require separate SOP instances for each stress level. However, a receiving AE is not expected to recombine them.

C.8.4.1 NM Series Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.4.2 NM Equipment Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.4.3 NM Image Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.4.4 NM Spect Acquisition Image Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.4.5 NM Multi-gated Acquisition Image Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.4.6 NM/PET Patient Orientation Module

Table C.8-5 specifies the Attributes that describe the NM/PET Patient Orientation.

Table C.8-5. NM/PET Patient Orientation Module Attributes

Attribute Name

Tag

Type

Attribute Description

Patient Orientation Code Sequence

(0054,0410)

2

Sequence that describes the orientation of the patient with respect to gravity. See Section C.8.4.6.1.1 for further explanation.

Zero or one item shall be included in this sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 19 “Patient Orientation”.

The Coding Scheme Designator (0008,0102) shall have an Enumerated Value of "99SDM" for historical reasons.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>Patient Orientation Modifier Code Sequence

(0054,0412)

2C

Patient Orientation Modifier. Required if needed to fully specify the orientation of the patient with respect to gravity. See Section C.8.4.6.1.2 for further explanation.

Zero or one item shall be included in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 20 “Patient Orientation Modifier”.

The Coding Scheme Designator (0008,0102) shall have an Enumerated Value of "99SDM" for historical reasons.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

Patient Gantry Relationship Code Sequence

(0054,0414)

2

Describes the orientation of the patient with respect to the gantry. See Section C.8.4.6.1.3 for further explanation.

Zero or one item shall be included in this sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 21 “Patient Equipment Relationship”.

The Coding Scheme Designator (0008,0102) shall have an Enumerated Value of "99SDM" for historical reasons.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.


C.8.4.6.1 NM/PET Patient Orientation Attribute Descriptions
C.8.4.6.1.1 Patient Orientation Code Sequence

The Patient Orientation Code Sequence (0054,0410) is used to describe the orientation of the patient with respect to gravity, and is independent of the position in the gantry.

C.8.4.6.1.2 Patient Orientation Modifier Code Sequence

The Patient Orientation Modifier Code Sequence (0054,0412) is used to modify or enhance the orientation specified by Patient Orientation Code Sequence (0054,0410).

C.8.4.6.1.3 Patient Gantry Relationship Code Sequence

Patient Gantry Relationship Code Sequence (0054,0414) is used to describe the patient direction within the gantry, such as head-first or feet-first. When imaging the extremities, these directions are related to normal anatomic position.

Example: In normal anatomic position, the fingers point towards the feet.

C.8.4.7 NM Image Pixel Module

Table C.8-6 specifies the Attributes that describe the pixel data of a NM image.

Table C.8-6. NM Image Pixel Module Attributes

Attribute Name

Tag

Type

Attribute Description

Samples per Pixel

(0028,0002)

1

Number of samples (color planes) in this image. The value shall be 1.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data. See Section C.8.4.7.1.1 for further explanation.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated.

Enumerated Values:

8

16

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample. Each sample shall have the same number of bits stored. The value shall be the same as the value in Bits Allocated (0028,0100).

High Bit

(0028,0102)

1

Most significant bit for pixel sample data. Each sample shall have the same high bit. Shall be one less than the value in Bits Stored (0028,0101).

Pixel Spacing

(0028,0030)

2

Physical distance in the patient between the center of each pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing, in mm. See Section 10.7.1.3 for further explanation of the value order.


C.8.4.7.1 NM Image Pixel Attribute Descriptions
C.8.4.7.1.1 Photometric Interpretation

Enumerated Values:

MONOCHROME2

PALETTE COLOR

See Section C.7.6.3.1.2 for definition of these terms.

C.8.4.8 NM Multi-frame Module

Table C.8-7 specifies the Attributes of a NM Multi-frame Image. This module is always included in a NM SOP instance, even if there is only one frame in the image.

A NM Image object is always a multi-dimensional multi-frame image. The order and organization of the frames within each image is defined by the Frame Increment Pointer (0028,0009). The Frame Increment Pointer (0028,0009) references one or more indexing vectors. An indexing vector is a 1 dimensional array with exactly one element for each frame in the image. The value of the nth element in the indexing vector represents the index for the nth frame, in that dimension. Indices are always numbered starting from 1.

Note

The scheme for encoding a multi-dimensional array of frames into a single image object is as follows. First, the definition of the data element called the Frame Increment Pointer is changed so that it can be multi-valued (i.e., its VM is now 1-n). Each value of Frame Increment Pointer represents one of the dimensions of the array, with the last value representing the most rapidly changing index. Each value of Frame Increment Pointer is the tag of a data element that is an indexing vector. An indexing vector is a 1 dimensional array with exactly one element for each frame in the image. The value of the nth element in the indexing vector represents the index for the nth frame, in that dimension. For example, suppose you are encoding a Dynamic image consisting of 2 phases (containing 5 and 2 frames, respectively), from each of two detectors, using one isotope, which gives a total of 14 frames in the image. For a Dynamic image, the Frame Increment Pointer is defined as:Frame Increment Pointer = Energy Window Vector (0054,0010) \ Detector Vector (0054,0020) \ Phase Vector (0054,0030) \ Time Slice Vector (0054,0100). Pixel Data (7FE0,0010) would contain the frames in the following order:

Frame

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Energy Window #

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Detector #

1

1

1

1

1

1

1

2

2

2

2

2

2

2

Phase #

1

1

1

1

1

2

2

1

1

1

1

1

2

2

Time Slice #

1

2

3

4

5

1

2

1

2

3

4

5

1

2

and the four vectors would be defined as:

Energy Window Vector = 1,1,1,1,1,1,1,1,1,1,1,1,1,1

Detector Vector = 1,1,1,1,1,1,1,2,2,2,2,2,2,2

Phase Vector = 1,1,1,1,1,2,2,1,1,1,1,1,2,2

Time Slice Vector = 1,2,3,4,5,1,2,1,2,3,4,5,1,2

The receiver can tell the relationship of all the frames from these four vectors. For instance, looking at the 11th value in these four vectors tells you that the 11th frame in this multi-frame object is time slice 4 of phase 1 from detector 2 and isotope 1.

The Energy Window, Detector, Phase, Rotation, R-R Interval, and Time Slot Vectors have corresponding sequence elements that contain exactly one sequence item for each of the index values in the vector. The sequence item contains a set of data elements that are specific to that group of frames, but change from one group to the next. In the above example there would be a detector sequence element, an isotope sequence element and a phase sequence element (for dynamics, no frame sequence element is needed). The detector and phase sequence elements would contain two sequence items (because there were 2 detectors and 2 phases).

Table C.8-7. NM Multi-frame Module Attributes

Attribute Name

Tag

Type

Attribute Description

Frame Increment Pointer

(0028,0009)

1

Contains the Data Element Tags of one or more frame index vectors. See Section C.8.4.8.1.1 for further specialization.

Energy Window Vector

(0054,0010)

1C

An array that contains the energy window number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Energy Window Vector (0054,0010). See Section C.8.4.8.1.2 for specialization.

Number of Energy Windows

(0054,0011)

1

Number of energy window groupings. See Section C.8.4.8.1.2 for specialization.

Detector Vector

(0054,0020)

1C

An array that contains the detector number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Detector Vector (0054,0020). See Section C.8.4.8.1.3 for specialization.

Number of Detectors

(0054,0021)

1

Number of detectors. See Section C.8.4.8.1.3 for specialization.

Phase Vector

(0054,0030)

1C

An array that contains the phase number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Phase Vector (0054,0030). See Section C.8.4.8.1.4 for specialization.

Number of Phases

(0054,0031)

1C

Number of phases. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Phase Vector (0054,0030). See Section C.8.4.8.1.4 for specialization.

Rotation Vector

(0054,0050)

1C

An array that contains the rotation number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Rotation Vector (0054,0050). See Section C.8.4.8.1.5 for specialization.

Number of Rotations

(0054,0051)

1C

Number of rotations. Required if Image Type (0008,0008), Value 3 is

TOMO,GATED TOMO,RECON TOMO, or RECON GATED TOMO.

See Section C.8.4.8.1.5 for specialization.

R-R Interval Vector

(0054,0060)

1C

An array that contains the R-R interval number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for R-R Interval Vector (0054,0060). See Section C.8.4.8.1.6 for specialization.

Number of R-R Intervals

(0054,0061)

1C

Number of R-R intervals. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for R-R Interval Vector (0054,0060). See Section C.8.4.8.1.6 for specialization.

Time Slot Vector

(0054,0070)

1C

An array that contains the time slot number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Time Slot Vector (0054,0070). See Section C.8.4.8.1.7 for specialization.

Number of Time Slots

(0054,0071)

1C

Number of time slots. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Time Slot Vector (0054,0070). See Section C.8.4.8.1.7 for specialization.

Slice Vector

(0054,0080)

1C

An array that contains the spatial slice number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Slice Vector (0054,0080). See Section C.8.4.8.1.8 for specialization.

Number of Slices

(0054,0081)

1C

Number of slices. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Slice Vector (0054,0080). See Section C.8.4.8.1.8 for specialization.

Angular View Vector

(0054,0090)

1C

An array that contains the angular view number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Angular View Vector (0054,0090). See Section C.8.4.8.1.9 for specialization.

Time Slice Vector

(0054,0100)

1C

An array that contains the time slice number for each frame. Required if the value of Frame Increment Pointer (0028,0009) includes the Tag for Time Slice Vector (0054,0100). See Section C.8.4.8.1.10 for specialization.


Note

Per the rules in PS3.5, if a data element of Type 1C or 2C is not required, it shall not be included.

C.8.4.8.1 NM Multi-frame Attribute Descriptions
C.8.4.8.1.1 Frame Increment Pointer

By definition, NM Images are multi-dimensional Multi-frame Images. The value of Frame Increment Pointer (0028,0009) contains the Tag for one or more frame indexing vectors. This determines the number of dimensions of frame indices in the image, and the order in which these indices vary from one frame to the next, with the last Tag indicating the most rapidly changing index. The Enumerated Values for Frame Increment Pointer (0028,0009) are determined by Image Type (0008,0008) Value 3, as shown in Table C.8-8.

Table C.8-8. Enumerated Values for Frame Increment Pointer

Image Type (0008,0008) Value 3

Frame Increment Pointer (0028,0009)

STATIC or WHOLE BODY

0054H 0010H \ 0054H 0020H Sequencing is by Energy Window Vector (0054,0010), Detector Vector (0054,0020).

DYNAMIC

0054H 0010H \ 0054H 0020H \ 0054H 0030H \ 0054H 0100H Sequencing is by Energy Window Vector (0054,0010), Detector Vector (0054,0020), Phase Vector (0054,0030), Time Slice Vector (0054,0100)

GATED

0054H 0010H \ 0054H 0020H \ 0054H 0060H \ 0054H 0070H Sequencing is by Energy Window Vector (0054,0010), Detector Vector (0054,0020), R-R Interval Vector (0054,0060), Time Slot Vector (0054,0070)

TOMO

0054H 0010H \ 0054H 0020H \ 0054H 0050H \ 0054H 0090H Sequencing is by Energy Window Vector (0054,0010), Detector Vector (0054,0020), Rotation Vector (0054,0050), Angular View Vector (0054,0090)

GATED TOMO

0054H 0010H \ 0054H 0020H \ 0054H 0050H \ 0054H 0060H \ 0054H 0070H \ 0054H 0090H

Sequencing is by Energy Window Vector (0054,0010), Detector Vector (0054,0020), Rotation Vector (0054,0050), R-R Interval Vector (0054,0060), Time Slot Vector (0054,0070), Angular View Vector (0054,0090).

RECON TOMO

0054H 0080H

Sequencing is by Slice Vector (0054,0080)

RECON GATED TOMO

0054H 0060H \ 0054H 0070H \ 0054H 0080H

Sequencing is by R-R Interval Vector (0054,0060), Time Slot Vector (0054,0070), Slice Vector (0054,0080)


C.8.4.8.1.2 Number of Energy Windows and Energy Window Vector

Number of Energy Windows (0054,0011) is the number of distinct energy window groupings acquired in this image. See Section C.8.4.10.1. When Image Type (0008,0008), Value 3, is RECON TOMO or RECON GATED TOMO, then the Number of Energy Windows (0054,0011) shall be 1.

Energy Window Vector (0054,0010) is an indexing vector. The value of the nth element of this vector is the energy window number for the nth frame in this image, and shall have a value from 1 to Number of Energy Windows (0054,0011).

C.8.4.8.1.3 Number of Detectors and Detector Vector

Number of Detectors (0054,0021) is the number of separate detectors that differentiate the frames in this image. When Image Type (0008,0008), Value 3, is RECON TOMO or RECON GATED TOMO, then the Number of Detectors (0054,0021) shall be 1.

Note

Number of Detectors (0054,0021) does not necessarily represent the actual number of detectors used during data acquisition.

Example 1: In a TOMO acquisition in which frames from 2 or more detectors are interleaved to form one continuous set of frames, then no distinction is made between frames on the basis of which detector created them. In this case, the Number of Detectors (0054,0021) would be 1.

Example 2: In a WHOLE BODY acquisition in which a single detector acquires anterior and posterior views in two separate passes, the Number of Detectors (0054,0021) would be 2.

Detector Vector (0054,0020) is an indexing vector. The value of the nth element of this vector is the detector number of the nth frame in this image, and shall have a value from 1 to Number of Detectors (0054,0021).

C.8.4.8.1.4 Number of Phases and Phase Vector

Number of Phases (0054,0031) is the number of dynamic phases, independent of the number of Detectors and Isotopes. See Section C.8.4.14 for definition of a phase.

Phase Vector (0054,0030) is an indexing vector. The value of the nth element of this vector is the phase number of the nth frame in this image, and shall have a value from 1 to Number of Phases (0054,0031).

C.8.4.8.1.5 Number of Rotations and Rotation Vector

Number of Rotations (0054,0051) is the number of separate rotations. See Section C.8.4.12 for definition of a rotation. When Image Type (0008,0008), Value 3, is RECON TOMO, GATED TOMO or RECON GATED TOMO, then the Number of Rotations (0054,0051) shall be 1.

Rotation Vector (0054,0050) is an indexing vector. The value of the nth element of this vector is the rotation number of the nth frame in this image, and shall have a value from 1 to Number of Rotations (0054,0051).

C.8.4.8.1.6 Number of R-R Intervals and R-R Interval Vector

Number of R-R Intervals (0054,0061) is the number of ranges of heartbeat durations collected. A gated acquisition may employ one R-R Interval to collect data from normal beats, a second R-R Interval to collect data from ectopic beats, and possibly others. Each R-R Interval accepts beats whose duration is greater than its Low R-R Value (0018,1081) and shorter than its High R-R Value (0018,1082). Beats that do not fall within these ranges may be accepted by another R-R Interval, or may be rejected.

The Number of R-R Intervals (0054,0061) is the total number of such ranges.

R-R Interval Vector (0054,0060) is an indexing vector. The value of the nth element of this vector is the interval number of the nth frame in this image, and shall have a value from 1 to Number of R-R Intervals (0054,0061).

C.8.4.8.1.7 Number of Time Slots and Time Slot Vector

Number of Time Slots (0054,0071) is the number of frames into which each gating event is divided in a gated acquisition. For example, in a cardiac gated acquisition, data from a number of heartbeats are then combined by summing together the first frames from all beats into a summed first frame, all the second frames into a summed second frame, and so on. The result has the same number of frames as the Number of Time Slots in each beat.

Time Slot Vector (0054,0070) is an indexing vector. The value of the nth element of this vector is the time slot number of the nth frame in this image, and shall have a value from 1 to Number of Time Slots (0054,0071).

C.8.4.8.1.8 Number of Slices and Slice Vector

Number of Slices (0054,0081) is the number of slices in each separate volume.

Note

For images with Image Type (0008,0008), Value 3, equal to RECON GATED TOMO this implies that Number of Slices (0054,0081) is the same for all R-R Intervals and Time Slots.

Slice Vector (0054,0080) is an indexing vector. The value of the nth element of this vector is the slice number of the nth frame in this image, and shall have a value from 1 to Number of Slices (0054,0081).

C.8.4.8.1.9 Angular View Vector

Angular View Vector (0054,0090) is an indexing vector. The value of the nth element of this vector is the angular view number of the nth frame in this image. If Image Type (0008,0008), Value 3, is TOMO or GATED TOMO, then the value shall be from 1 to Number of Frames in Rotation (0054,0053).

C.8.4.8.1.10 Time Slice Vector

Time Slice Vector (0054,0100) is an indexing vector. The value of the nth element of this vector is the time slice number of the nth frame in this image, and shall have a value from 1 to Number of Frames in Phase (0054,0033).

C.8.4.9 NM Image Module

Table C.8-9 contains the Attributes that describe Nuclear Medicine Images.

Table C.8-9. NM Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Image Type

(0008,0008)

1

Image identification characteristics. See Section C.8.4.9.1.1 for specialization.

Image ID

(0054,0400)

3

User or equipment generated Image identifier.

Lossy Image Compression

(0028,2110)

1C

Specifies whether an Image has undergone lossy compression (at a point in its lifetime).

Enumerated Values:

00

Image has NOT been subjected to lossy compression.

01

Image has been subjected to lossy compression.

Once this value has been set to 01 it shall not be reset.

See Section C.7.6.1.1.5

Required if Lossy Compression has been performed on the Image. May be present otherwise.

Counts Accumulated

(0018,0070)

2

Sum of all gamma events for all frames in the image. See Section C.8.4.9.1.2 for specialization.

Acquisition Termination Condition

(0018,0071)

3

Description of how the data collection was stopped.

Defined Terms:

CNTS

counts

DENS

density

MANU

manual

OVFL

data overflow

TIME

time

TRIG

physiological trigger

See Section C.8.4.9.1.3 for specialization.

Table Height

(0018,1130)

3

The height of the patient table in mm. The range and values of this element are determined by the manufacturer. Should not be included if Image Type (0008,0008), Value 3, is

TOMO,GATED TOMO,RECON TOMO or RECON GATED TOMO.

Table Traverse

(0018,1131)

3

Location of the patient table (or gantry relative to the table) in mm. The range and values of this element are determined by the manufacturer. Should not be included if Image Type (0008,0008), Value 3, is

TOMO,GATED TOMO,RECON TOMO or RECON GATED TOMO.

Actual Frame Duration

(0018,1242)

1C

Elapsed time for data acquisition in msec. Required if Image Type (0008,0008) Value 3 is:

WHOLE BODY or

STATIC.

See Section C.8.4.9.1.4 for specialization.

Count Rate

(0018,1243)

3

Maximum count rate achieved during the acquisition in counts/sec.

Processing Function

(0018,5020)

3

Code or description of processing functions applied to the data.

Corrected Image

(0028,0051)

3

One or more values that indicate which, if any, corrections have been applied to the image. Corrections are applied to all frames in the image.

Defined Terms:

UNIF

flood corrected

COR

center of rotation corrected

NCO

non-circular orbit corrected

DECY

decay corrected

ATTN

attenuation corrected

SCAT

scatter corrected

DTIM

dead time corrected

NRGY

energy corrected

LIN

linearity corrected

MOTN

motion corrected

CLN

count loss normalization; Any type of normalization applied to correct for count loss in Time Slots.

Whole Body Technique

(0018,1301)

3

The type of scan performed. Used only if Image Type (0008,0008), Value 3, contains the value WHOLE BODY.

Enumerated Values:

1PS

one pass

2PS

two pass

PCN

patient contour following employed

MSP

multiple static frames collected into a whole body frame

Scan Velocity

(0018,1300)

2C

The speed of the camera motion over the body in mm/sec. Required if Image Type (0008,0008) Value 3 contains the value WHOLE BODY.

Scan Length

(0018,1302)

2C

Size of the imaged area in the direction of scanning motion, in mm. Required if Image Type (0008,0008) Value 3 contains the value WHOLE BODY.

Trigger Source or Type

(0018,1061)

3

Text indicating trigger source.

Defined Terms:

EKG

Include Table 10-7 “General Anatomy Optional Macro Attributes”

No Context ID for the Anatomic Region Sequence is defined.

Real World Value Mapping Sequence

(0040,9096)

3

The mapping of stored values to associated real world values.

One or more Items are permitted in this sequence.

>Include Table C.7.6.16-12b “Real World Value Mapping Item Macro Attributes”

Defined CID for Measurement Units Code Sequence is 84 "PET Units for Real World Value Mapping".

Scan Progression Direction

(0054,0501)

3

The anatomical order in which the slices were acquired.

Enumerated Values:

FEET_TO_HEAD

Slices closest to the patient's feet were acquired first.

HEAD_TO_FEET

Slices closest to the patient's head were acquired first.


Note

  1. Content Date (0008,0023) and Content Time (0008,0033) are included in the General Image Module, Table C.7-7, whenever the images are temporally related. For this purpose, all NM Images are considered temporally related, so that these elements are included in an NM Image.

  2. Referenced Overlay Sequence (0008,1130) and Referenced Curve Sequence (0008,1145) were previously included in this Module as optional Attributes but have been retired. See PS3.3-2004. Referenced Image Real World Value Mapping Sequence (0040,9094) was previously used in this Module to enclose the Real World Value Mapping Sequence (0040,9096) but has been retired. See PS3.3-2011.

C.8.4.9.1 NM Image Module Attribute Descriptions
C.8.4.9.1.1 Image Type

For NM images, Image Type (0008,0008) Value 3 is specified to be Type 1.

Enumerated Values for Value 3:

STATIC

DYNAMIC

GATED

WHOLE BODY

TOMO

GATED TOMO

RECON TOMO

RECON GATED TOMO

Enumerated Values for Value 4:

EMISSION

TRANSMISSION

Note

For NM images, Image Type (0008,0008) Value 1 will be ORIGINAL for all raw data and reconstructed images. DERIVED may be appropriate for some other results images.

For NM images, Image Type (0008,0008) Value 2 will be PRIMARY.

C.8.4.9.1.2 Counts Accumulated

Counts Accumulated (0018,0070) is the total of all gamma events accumulated in all frames of this Image. This attribute applies to acquisition data, and often does not apply to processed images (DERIVED, SECONDARY).

C.8.4.9.1.3 Acquisition Termination Condition

Acquisition Termination Condition (0018,0071) is the method of acquisition termination that was actually applied to the data collection.

Defined Terms:

CNTS

preset count limit was reached

DENS

preset count density was reached

MANU

acquisition was terminated manually

OVFL

acquisition was terminated automatically by pixel data overflow condition

TIME

preset time limit was reached

TRIG

preset number of physiological triggers was reached

C.8.4.9.1.4 Actual Frame Duration

Actual Frame Duration (0018,1242) is defined as the elapsed time in msec for a single frame of an acquisition. For some types of multi-frame images, Actual Frame Duration (0018,1242) may have a more specialized meaning as defined in the appropriate IOD Module.

C.8.4.10 NM Isotope Module

Table C.8-10 contains Attributes that describe the isotope administered for the acquisition.

Table C.8-10. NM Isotope Module Attributes

Attribute Name

Tag

Type

Attribute Description

Energy Window Information Sequence

(0054,0012)

2

Sequence of Items that describe the energy window groups used.

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of Energy Windows (0054,0011). The first item corresponds to frames with value of 1 in the Energy Window Vector (0054,0010), the second item with value 2, etc.

>Energy Window Name

(0054,0018)

3

A user defined name that describes this Energy Window.

>Energy Window Range Sequence

(0054,0013)

3

Sequence of Items that describes this energy window group.

One or more Items are permitted in this Sequence.

>>Energy Window Lower Limit

(0054,0014)

3

The lower limit of the energy window in KeV. See Section C.8.4.10.1.1 for further explanation.

>>Energy Window Upper Limit

(0054,0015)

3

The upper limit of the energy window in KeV. See Section C.8.4.10.1.2 for further explanation.

Radiopharmaceutical Information Sequence

(0054,0016)

2

Sequence of Items that describe isotope information.

Zero or more Items shall be included in this sequence.

>Radionuclide Code Sequence

(0054,0300)

2

Sequence that identifies the radionuclide.

Zero or one item shall be included in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 18 “Isotopes in Radiopharmaceuticals”.

The Coding Scheme Designator (0008,0102) shall have an Enumerated Value of "99SDM" for historical reasons.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>Radiopharmaceutical Route

(0018,1070)

3

Route of injection.

>Administration Route Code Sequence

(0054,0302)

3

Sequence that identifies the administration route for the radiopharmaceutical.

Only a single Item is permitted in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 11 “Route of Administration”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>Radiopharmaceutical Volume

(0018,1071)

3

Volume of injection in cubic cm.

>Radiopharmaceutical Start Time

(0018,1072)

3

Time of start of injection. See Section C.8.4.10.1.5 for further explanation.

>Radiopharmaceutical Stop Time

(0018,1073)

3

Time of end of injection. See Section C.8.4.10.1.6 for further explanation.

>Radionuclide Total Dose

(0018,1074)

3

Total amount of radionuclide injected. See Section C.8.4.10.1.7 for further explanation.

>Radiopharmaceutical Administration Event UID

(0008,3012)

3

Unique identification of the administration of the radiopharmaceutical to the patient.

Note

The UID is the same Radiopharmaceutical Administration Event UID that is in the Radiopharmaceutical Radiation Dose Report.

>Calibration Data Sequence

(0054,0306)

3

Sequence that contains calibration data.

One or more Items are permitted in this Sequence.

>>Energy Window Number

(0054,0308)

1

The Item number in the Energy Window Information Sequence to which the following calibration data relates. The Items are numbered starting from 1.

>>Syringe Counts

(0018,1045)

3

Pre-injection syringe count rate in counts/sec. See Section C.8.4.10.1.8 for further explanation.

>>Residual Syringe Counts

(0054,0017)

3

Post-injection residue syringe count rate in counts/sec. See Section C.8.4.10.1.9 for further explanation.

>Radiopharmaceutical

(0018,0031)

3

Name of the radiopharmaceutical.

>Radiopharmaceutical Code Sequence

(0054,0304)

3

Sequence that identifies the radiopharmaceutical.

Only a single Item is permitted in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 25 “Radiopharmaceuticals”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

Intervention Drug Information Sequence

(0018,0026)

3

Sequence of Items that describes the intervention drugs used. One or more Items are permitted in this sequence.

>Intervention Drug Name

(0018,0034)

3

Name of intervention drug.

>Intervention Drug Code Sequence

(0018,0029)

3

Sequence that identifies the intervention drug name.

Only a single Item is permitted in this Sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 10 “Interventional Drug”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>Administration Route Code Sequence

(0054,0302)

3

Sequence that identifies the administration route for the intervention drug.

Only a single Item is permitted in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 11 “Route of Administration”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>Intervention Drug Start Time

(0018,0035)

3

Time of administration of the intervention drug, using the same time base as for Acquisition Time (0008,0032).

>Intervention Drug Stop Time

(0018,0027)

3

Time of completion of administration of the intervention drug, using the same time base as for Acquisition Time (0008,0032).

>Intervention Drug Dose

(0018,0028)

3

Intervention drug dose, in mg.


C.8.4.10.1 NM Isotope Module Attribute Descriptions
C.8.4.10.1.1 Energy Window Lower Limit

Energy Window Lower Limit (0054,0014) is the acquisition energy window lower limit in KeV for acceptance of scintillation events into this Isotope.

C.8.4.10.1.2 Energy Window Upper Limit

Energy Window Upper Limit (0054,0015) is the acquisition energy window upper limit in KeV for acceptance of scintillation events into this Isotope.

C.8.4.10.1.3 (Retired)

C.8.4.10.1.4 (Retired)

C.8.4.10.1.5 Radiopharmaceutical Start Time

Radiopharmaceutical Start Time (0018,1072) is the actual time of radiopharmaceutical administration to the patient for imaging purposes, using the same time base as for Acquisition Time (0008,0032).

C.8.4.10.1.6 Radiopharmaceutical Stop Time

Radiopharmaceutical Stop Time (0018,1073) is the actual ending time of radiopharmaceutical administration to the patient for imaging purposes, using the same time base as for Acquisition Time (0008,0032).

C.8.4.10.1.7 Radionuclide Total Dose

Radionuclide Total Dose (0018,1074) is the radiopharmaceutical dose administered to the patient measured in MegaBecquerels (Mbq) at the Radiopharmaceutical Start Time.

C.8.4.10.1.8 Syringe Counts

Syringe Counts (0018,1045) is the pre-injection syringe acquisition count rate measured in counts/sec, corrected to Acquisition Time (0008,0032) if necessary.

C.8.4.10.1.9 Residual Syringe Counts

Residual Syringe Counts (0054,0017) is the syringe acquisition count rate following patient injection, measured in counts/sec, corrected to Acquisition Time (0008,0032) if necessary.

C.8.4.10.1.10 (Retired)

C.8.4.10.1.11 (Retired)

C.8.4.11 NM Detector Module

Table C.8-11 contains IOD Attributes that describe Nuclear Medicine Detectors used to produce an image.

Table C.8-11. NM Detector Module Attributes

Attribute Name

Tag

Type

Attribute Description

Detector Information Sequence

(0054,0022)

2

Sequence of Items that describe the detectors used.

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of Detectors (0054,0021). The first item corresponds to frames with value of 1 in Detector Vector (0054,0020), the second item with value 2, etc.

>Collimator/Grid Name

(0018,1180)

3

Label describing the collimator used (LEAP, hires, etc.)

>Collimator Type

(0018,1181)

2

Collimator type.

Defined Terms:

PARA

Parallel (default)

PINH

Pinhole

FANB

Fan-beam

CONE

Cone-beam

SLNT

Slant hole

ASTG

Astigmatic

DIVG

Diverging

NONE

No collimator

UNKN

Unknown

>Field of View Shape

(0018,1147)

3

Shape of the field of view of the Nuclear Medicine detector.

Defined Terms:

RECTANGLE

ROUND

HEXAGONAL

>Field of View Dimension(s)

(0018,1149)

3

Dimensions of the field of view, in mm. If Field of View Shape (0018,1147) is:

RECTANGLE: row dimension followed by column.

ROUND: diameter.

HEXAGONAL: diameter of a circumscribed circle.

>Focal Distance

(0018,1182)

2

Focal distance, in mm. A value of 0 means infinite distance for parallel collimation. See Section C.8.4.11.1.1 for further specialization.

>X Focus Center

(0018,1183)

3

Center of focus along a row. See Section C.8.4.11.1.2 for further explanation.

>Y Focus Center

(0018,1184)

3

Center of focus along a column. See Section C.8.4.11.1.2 for further explanation.

>Zoom Center

(0028,0032)

3

The amount of offset from (0,0) applied to each pixel in the image before application of the zoom factor, specified by a numeric pair: row value (delimiter) column value (in mm). See Section C.8.4.11.1.3 for further explanation.

>Zoom Factor

(0028,0031)

3

The amount of magnification applied to each pixel in the image, specified by a numeric pair: row value (delimiter) column value. See Section C.8.4.11.1.4 for further explanation.

>Center of Rotation Offset

(0018,1145)

3

Average center of rotation offset of Nuclear Medicine detector in mm. See Section C.8.4.11.1.5 for further explanation.

>Gantry/Detector Tilt

(0018,1120)

3

Angle of tilt in degrees of the detector. See Section C.8.4.11.1.6 for further explanation.

>Distance Source to Detector

(0018,1110)

2C

Distance in mm from transmission source to the detector face. Required if Image Type (0008,0008) Value 4 is TRANSMISSION and Value 3 is not any of TOMO,GATED TOMO,RECON TOMO or RECON GATED TOMO.

>Start Angle

(0054,0200)

3

Position of the detector about the patient for the start of the acquisition, in degrees. Zero degrees is referenced to the origin at the patient's back. Viewing from the patient's feet, angle increases in a counter-clockwise direction (detector normal rotating from the patient's back towards the patient's left side). Should not be included if Image Type (0008,0008) Value 3 is TOMO, GATED TOMO, RECON TOMO or RECON GATED TOMO.

>Radial Position

(0018,1142)

3

Radial distance of the detector from the center of rotation, in mm. Should not be included if Image Type (0008,0008) Value 3 is TOMO, GATED TOMO, RECON TOMO or RECON GATED TOMO.

>Image Orientation (Patient)

(0020,0037)

2

The direction cosines of the first row and the first column with respect to the patient. See Section C.7.6.2.1.1 for further explanation.

>Image Position (Patient)

(0020,0032)

2

The x, y, and z coordinates of the upper left hand corner (center of the first voxel transmitted) of the image, in mm. See Section C.7.6.2.1.1 for further explanation.

>View Code Sequence

(0054,0220)

3

Sequence that describes the projection of the anatomic region of interest on the image receptor.

Only a single Item is permitted in this sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 26 “Nuclear Medicine Projections”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.

>>View Modifier Code Sequence

(0054,0222)

2C

View Modifier. Required if needed to fully specify the View.

Zero or one Item shall be included in this sequence.

>>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 23 “Cranio-Caudad Angulation”.

Code Meaning (0008,0104) shall be Type 3 for historical reasons.


C.8.4.11.1 NM Detector Attribute Descriptions
C.8.4.11.1.1 Focal Distance

Focal Distance (0018,1182) for NM Image data is the focal distance, in mm for converging or diverging collimators, measured from the front face of the detector to the focus. Positive values indicate converging and negative values indicate diverging collimators. A value of 0 means infinite distance for parallel collimation.

C.8.4.11.1.2 Focus Center

X Focus Center (0018,1183) and Y Focus Center (0018,1184) for NM Image data is used to define the projection of the focus for a converging or diverging collimator within the un-zoomed Field of View. It is defined in mm for row and column relative to the center of the un-zoomed Field of View.

C.8.4.11.1.3 Zoom Center

Zoom Center (0028,0032) is the offset between the un-zoomed camera field of view and field of view, measured from the center of the un-zoomed camera field of view to the center the of the zoomed field of view. The offset is measured in mm in the un-zoomed camera FOV dimensions. Positive values are to the right and down from the un-zoomed center, as viewed from the image plane. When this attribute is not given, the Zoom Center is assumed to be 0\0.

C.8.4.11.1.4 Zoom Factor

Zoom Factor (0028,0031) is the magnification factor that was used during the acquisition. When this attribute is not given, it is assumed to be 1.0\1.0.

Note

Zoom Factor (0028,0031) is informational only. Pixel Spacing (0028,0030) already takes account of this and any other changes to pixel size.

C.8.4.11.1.5 Center of Rotation Offset

Center of Rotation Offset (0018,1145) is the average amount of offset in mm between the Detector Field of View center and the physical center of rotation of the gantry for circular orbital scans. Positive values indicate the physical center is to the right of the image plane center.

If:

  1. Image Type (0008,0008) Value 3 is TOMO or GATED TOMO, and

  2. Corrected Image (0028,0051) does not include the value "COR", and

  3. Center of Rotation Offset (0018,1145) is non-zero,

then the receiver should assume that Center of Rotation correction has not already been done.

If the Center of Rotation Offset is zero, no correction shall be applied.

C.8.4.11.1.6 Gantry/Detector Tilt

Gantry/Detector Tilt (0018,1120) for NM Image data is the angle in degrees of the detector face relative to the patient's major (Head to Feet) axis (or the table supporting the patient). Positive tilt is towards the patient's feet.

C.8.4.12 NM Tomo Acquisition Module

This Module applies to a TOMO Multi-frame Image. This module is present when Image Type (0008,0008) Value 3, is equal to TOMO, GATED TOMO, RECON TOMO, or RECON GATED TOMO. The elements found in this module describe the acquisition of the Image.

Table C.8-12. NM Tomo Acquisition Module Attributes

Attribute Name

Tag

Type

Attribute Description

Rotation Information Sequence

(0054,0052)

2

Sequence of Items that describe TOMO rotational groups. A new rotation is defined whenever the direction of the detector motion changes, or Table Traverse (0018,1131) changes.

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of Rotations (0054,0051). If Rotation Vector (0054,0050) is present, the first item corresponds to frames with value of 1 in Rotation Vector (0054,0050), the second item with value 2, etc.

>Start Angle

(0054,0200)

1

Position of the detector about the patient for the start of this rotation, in degrees. Zero degrees is referenced to the origin at the patient's back. Viewing from the patient's feet, angle increases in a counter-clockwise direction (detector normal rotating from the patient's back towards the patient's left side).

>Angular Step

(0018,1144)

1

The angular scan arc step between views of the TOMO acquisition, in degrees. See Section C.8.4.12.1.1 for further explanation.

>Rotation Direction

(0018,1140)

1

Direction of rotation of the detector about the patient. See Start Angle (0054,0200) for further explanation of direction.

Enumerated Values:

CW

clockwise (decreasing angle)

CC

counter-clockwise (increasing angle).

>Scan Arc

(0018,1143)

1

The effective angular range of the scan data in degrees. The value shall be positive.

>Actual Frame Duration

(0018,1242)

1

Nominal acquisition time per angular position, in msec.

>Radial Position

(0018,1142)

3

Radial distance of the detector from the center of rotation, in mm. It shall have a single value that is an average value for this rotation, or it shall have one value per angular view.

>Distance Source to Detector

(0018,1110)

2C

Distance in mm from transmission source to the detector face. Required if Image Type (0008,0008) Value 4 is TRANSMISSION.

>Number of Frames in Rotation

(0054,0053)

1

Number of angular views in this rotation.

>Table Traverse

(0018,1131)

3

Location of the patient table (or gantry relative to the table) in mm. The range and values of this element are determined by the manufacturer.

>Table Height

(0018,1130)

3

The distance in mm of the top of the patient table to the center of rotation. Table height below the center of rotation has a positive value.

Type of Detector Motion

(0054,0202)

3

Describes the detector motion during acquisition.

Enumerated Values:

STEP AND SHOOT

Interrupted motion, acquire only while stationary

CONTINUOUS

Gantry motion and acquisition are simultaneous and continuous

ACQ DURING STEP

Interrupted motion, acquisition is continuous


C.8.4.12.1 NM Tomo Acquisition Attribute Descriptions
C.8.4.12.1.1 Angular Step

Angular Step (0018,1144) is the nominal frame-to-frame incremental angle for TOMO and GATED TOMO acquisition images, defined in degrees. Angular Step (0018,1144) shall be a positive number. Summation of Angular Step values is not defined to give accurate Angular Position or Scan Arc values. The Angular Step is the effective angular spacing between resultant frames of the Multi-framed planar image data.

C.8.4.13 NM Multi-gated Acquisition Module

Table C.8-13 contains Attributes that describe a multi-gated acquisition image performed on the patient. This refers to frames acquired while the patient is connected to a gating device.

Table C.8-13. NM Multi-Gated Acquisition Module Attributes

Attribute Name

Tag

Type

Attribute Description

Beat Rejection Flag

(0018,1080)

3

Heart beat duration sorting has been applied.

Enumerated Values:

Y

yes

N

no

PVC Rejection

(0018,1085)

3

Description of type of arrhythmic beat rejection criteria used.

Skip Beats

(0018,1086)

3

Number of beats skipped after a detected arrhythmia

Heart Rate

(0018,1088)

3

Average number of heart beats per minute for the collection period for these frames. This shall include all accepted beats as well as rejected beats.

Gated Information Sequence

(0054,0062)

2C

Sequence of Items that describe R-R intervals. Each gated interval is defined by an upper and lower range of heart beat durations. Required if the Frame Increment Pointer (0028,0009) contains the Tag for R-R Interval Vector (0054,0060).

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of R-R Intervals (0054,0061). The first item corresponds to frames with value of 1 in the R-R Interval Vector (0054,0060), the second item with value 2, etc.

>Trigger Time

(0018,1060)

3

Time interval measured in msec from the start of the R-wave to the beginning of the data taking.

>Cardiac Framing Type

(0018,1064)

3

Description of type of framing performed.

See Section C.7.6.18.1.1.1 for description and Defined Terms.

>Data Information Sequence

(0054,0063)

2

Sequence of Items that describe gating criteria.

Zero or more Items shall be included in this sequence.

See Section C.8.4.13.1.1.

>>Frame Time

(0018,1063)

1

Nominal time per individual frame in msec.

>>Nominal Interval

(0018,1062)

3

Average duration of accepted beats, in msec.

>>Low R-R Value

(0018,1081)

3

R-R interval lower limit for beat rejection, in msec

>>High R-R Value

(0018,1082)

3

R-R interval upper limit for beat rejection, in msec

>>Intervals Acquired

(0018,1083)

3

Number of heartbeats that fall within Low R-R Value (0018,1081) and High R-R Value (0018,1082), and were therefore accepted and contribute gamma events to this R-R Interval.

>>Intervals Rejected

(0018,1084)

3

Number of heartbeats that fall outside Low R-R (0018,1081) and High R-R Value (0018,1082), and do not contribute gamma events to this R-R Interval. However, they may contribute gamma events to other R-R Intervals.

>>Time Slot Information Sequence

(0054,0072)

2C

Sequence of Items that describe Time Slot Information. Required if the Frame Increment Pointer (0028,0009) contains the Tag for Time Slot Vector (0054,0070).

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of Time Slots (0054,0071). The first item corresponds to frames with value of 1 in the Time Slot Vector (0054,0070), the second item with value 2, etc.

>>>Time Slot Time

(0054,0073)

3

The total amount of time, in msec, that the acquisition accumulates gamma events into this frame. See Section C.8.4.13.1.2.


C.8.4.13.1 NM Multi-gated Acquisition Attribute Descriptions
C.8.4.13.1.1 Data Information Sequence

Data Information Sequence (0054,0063) shall contain a single sequence item that applies to the sum of all angular views, except when Image Type (0008,0008) Value 3 is GATED TOMO. In this case it shall have either a single item that applies to the sum of all angular views, or it shall have one item for each angular view.

C.8.4.13.1.2 Time Slot Time

The Time Slot Time (0054,0073) records the effective imaging time of each Time Slot. For example, if some of the accepted beats are shorter than others then the last frames may not receive a contribution from the shorter beats. The Time Slot Time for a Time Slot is the total acquisition time for that Time Slot. It is approximately equal to Frame Time (0018,1063) multiplied by the number of accepted beats contributing to the Time Slot.

C.8.4.14 NM Phase Module

Table C.8-14 contains Attributes that describe dynamic phases of a dynamic acquisition image performed on the patient. This module is present only when Image Type (0008,0008), Value 3, is equal to DYNAMIC. A phase is defined as a collection of frames in which the acquisition time per frame and the time delay between frames remains constant. A new phase shall be defined whenever there is a change in the time between frames, the acquisition time per frame, or the position of the patient relative to the detector.

Table C.8-14. NM Phase Module Attributes

Attribute Name

Tag

Type

Attribute Description

Phase Information Sequence

(0054,0032)

2C

Sequence of Items that describes each dynamic phase. Required if the Frame Increment Pointer (0028,0009) contains the Tag for Phase Vector (0054,0030).

Zero or more Items shall be included in this sequence.

The number of items shall be equal to Number of Phases (0054,0031). The first item corresponds to frames with value of 1 in Phase Vector (0054,0030), the second item with value 2, etc.

>Phase Delay

(0054,0036)

1

Time paused between the last frame of the previous phase and the first frame of this phase, in msec.

>Actual Frame Duration

(0018,1242)

1

Nominal time of acquisition per individual frame, in msec.

>Pause Between Frames

(0054,0038)

1

Time paused between each frame of this phase (in msec).

>Number of Frames in Phase

(0054,0033)

1

Number of frames in this phase.

>Trigger Vector

(0054,0210)

3

An array of trigger times when gating information is acquired simultaneously with the dynamic image data. See Section C.8.4.14.1.1 for further explanation.

>Number of Triggers in Phase

(0054,0211)

1C

The number of entries in Trigger Vector (0054,0210) for this phase. Required if Trigger Vector (0054,0210) is present.

>Phase Description

(0054,0039)

3

Description of this phase of the Dynamic image.

Enumerated Values:

FLOW

WASHOUT

UPTAKE

EMPTYING

EXCRETION


C.8.4.14.1 NM Phase Module Attributes Description
C.8.4.14.1.1 Trigger Vector

Trigger Vector (0054,0210) is an array containing a list of the inter-trigger interval times in milliseconds in the order in which they were acquired, with the first being measured from the start time of the first frame of the image data in the Phase. If this element is used, the start times are required to be the same so that a mathematical correlation can be made between trigger times and frame start times.

C.8.4.15 NM Reconstruction Module

Table C.8-15 contains Attributes that describe Nuclear Medicine reconstructed volumes. Reconstructed volumes are created by applying a transformation (reconstruction) process to the acquired TOMO frames. This module is present only when Image Type (0008,0008) Value 3 is equal to RECON TOMO or RECON GATED TOMO.

Table C.8-15. NM Reconstruction Module Attributes

Attribute Name

Tag

Type

Attribute Description

Spacing Between Slices

(0018,0088)

2

Spacing between slices, in mm, measured from center-to-center of each slice along the normal to the first image. The sign of the Spacing Between Slices (0018,0088) determines the direction of stacking. The normal is determined by the cross product of the direction cosines of the first row and first column of the first frame, such that a positive spacing indicates slices are stacked behind the first slice and a negative spacing indicates slices are stacked in front of the first slice. See Image Orientation (0020,0037) in the NM Detector module.

Reconstruction Diameter

(0018,1100)

3

Diameter, in mm, of the region from within which the data was used in creating the reconstruction of the image. Data may exist outside this region and portions of the patient may exist outside this region.

Convolution Kernel

(0018,1210)

3

A label describing the convolution kernel or algorithm used to reconstruct the data.

Slice Thickness

(0018,0050)

2

Nominal slice thickness, in mm.

Slice Location

(0020,1041)

3

Relative position of the image plane expressed in mm.

See Section C.7.6.2.1.2 for further explanation.

Slice Progression Direction

(0054,0500)

3

Describes the anatomical direction that slices are progressing as the slices are considered in order (as defined by Slice Vector (0054,0080)). Meaningful only for cardiac images.

When View Code Sequence (0054,0220) indicates a short axis view, then the Enumerated Values are:

Enumerated Values:

APEX_TO_BASE

BASE_TO_APEX


C.8.5 Ultrasound Modules

This Section describes Ultrasound Frame of Reference and Image Modules. These Modules contain Attributes that are specific to Ultrasound images.

C.8.5.1 US Frame of Reference Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.5.2 US Region Calibration (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.5.3 US Image Module (Retired)

This Section was defined in a previous version of the DICOM Standard. The Section is now retired.

C.8.5.4 US Frame of Reference Module

This Section was defined in a previous version of the DICOM Standard. The Section is now retired. See PS3.3-2003.

C.8.5.5 US Region Calibration Module

The US Region Calibration Module has been introduced into the ultrasound IOD to provide access to the full range of data that may be present in a single US image. US images often contain multiple regions that have independent data regions, e.g., quad screen loops that may have different calibration information. The data presented in the various regions of a US image can represent a multiplicity of physical parameters, e.g., spatial distance, blood velocity, time, volume, etc., and these are often contained in the value of the pixel itself. It is therefore imperative that physical information be available for the various regions of a single region independent of each other.

Table C.8-17 contains IOD Attributes that describe an ultrasound region calibration.

Table C.8-17. US Region Calibration Module Attributes

Attribute Name

Tag

Type

Attribute Description

Sequence of Ultrasound Regions

(0018,6011)

1

Defines a sequence of Ultrasound Regions.

One or more Items shall be included in this Sequence.

>Region Location Min x0

(0018,6018)

1

The bounds of a rectangle specifying the location of the region, x0,y0,x1,y1.

See Section C.8.5.5.1.14 for further explanation.

>Region Location Min y0

(0018,601A)

1

The bounds of a rectangle specifying the location of the region, x0,y0,x1,y1.

See Section C.8.5.5.1.14 for further explanation.

>Region Location Max x1

(0018,601C)

1

The bounds of a rectangle specifying the location of the region, x0,y0,x1,y1.

See Section C.8.5.5.1.14 for further explanation.

>Region Location Max y1

(0018,601E)

1

The bounds of a rectangle specifying the location of the region, x0,y0,x1,y1.

See Section C.8.5.5.1.14 for further explanation.

>Physical Units X Direction

(0018,6024)

1

The physical units of the dimensions of the region.

See Section C.8.5.5.1.15 for Enumerated Values.

>Physical Units Y Direction

(0018,6026)

1

The physical units of the dimensions of the region.

See Section C.8.5.5.1.15 for Enumerated Values.

>Physical Delta X

(0018,602C)

1

The physical value increments per positive X pixel increment. The units are as specified in the Physical Units X Direction (0018,6024).

See Section C.8.5.5.1.17 for further explanation.

>Physical Delta Y

(0018,602E)

1

The physical value increments per positive Y pixel increment. The units are as specified in the Physical Units Y Direction (0018,6026).

See Section C.8.5.5.1.17 for further explanation.

>Reference Pixel x0

(0018,6020)

3

This coordinate pair, x0,y0, defines the location of a virtual "reference" pixel.

See Section C.8.5.5.1.16 for further explanation.

>Reference Pixel y0

(0018,6022)

3

This coordinate pair, x0,y0, defines the location of a virtual "reference" pixel.

See Section C.8.5.5.1.16 for further explanation.

>Reference Pixel Physical Value X

(0018,6028)

3

The Physical Value at the reference pixel x location. The units are specified in the Physical Units field.

>Reference Pixel Physical Value Y

(0018,602A)

3

The Physical Value at the reference pixel y location. The units are specified in the Physical Units field.

>Region Spatial Format

(0018,6012)

1

The spatial organization of the data within the region.

See Section C.8.5.5.1.1 for Enumerated Values.

>Region Data Type

(0018,6014)

1

The type of data within the region.

See Section C.8.5.5.1.2 for Enumerated Values.

>Region Flags

(0018,6016)

1

Flags used for special handling of the region.

See Section C.8.5.5.1.3 for Enumerated Values and further explanation.

>Pixel Component Organization

(0018,6044)

1C

Describes how the components of a pixel can be described. Required if pixel component calibration exists for this region.

See Section C.8.5.5.1.4 for Enumerated Values and further explanation.

>Pixel Component Mask

(0018,6046)

1C

This value is ANDed with the composite pixel code for each pixel within the region, then shifted right by the number of contiguous least significant zeros in the mask to obtain what will be referred to as the "Shifted Masked Composite Pixel Code" (SMCPC). Required if Pixel Component Organization = Bit aligned.

See Section C.8.5.5.1.5 for further explanation.

>Pixel Component Range Start

(0018,6048)

1C

Defines the start of the numeric range of values within the composite pixel where calibration is to be defined by the "pixel physical calibration table". To be used only when ranges are used to describe the portion of the composite pixel.

Required if Pixel Component Organization = Ranges.

>Pixel Component Range Stop

(0018,604A)

1C

Defines the stop of the numeric range of values within the composite pixel where calibration is to be defined by the "pixel physical calibration table". To be used only when ranges are used to describe the portion of the composite pixel.

Required if Pixel Component Organization = Ranges.

>Pixel Component Physical Units

(0018,604C)

1C

The physical units to be applied to the pixel component.

Required if Pixel Component Organization exists.

See Section C.8.5.5.1.6 for further explanation.

>Pixel Component Data Type

(0018,604E)

1C

The type of data for the pixel component.

Required if Pixel Component Organization exists.

See Section C.8.5.5.1.7 for further explanation.

>Number of Table Break Points

(0018,6050)

1C

The number of break point coordinate pairs used to describe a piece wise linear curve.

Required if Pixel Component Organization equals 0 or 1. Otherwise not used.

See Section C.8.5.5.1.8 for further explanation.

>Table of X Break Points

(0018,6052)

1C

An array of X values used to create the piece wise linear curve.

Required if Pixel Component Organization equals 0 or 1. Otherwise not used.

See Section C.8.5.5.1.9 for further explanation.

>Table of Y Break Points

(0018,6054)

1C

An array of Y values used to create the piece wise linear curve.

Required if Pixel Component Organization equals 0 or 1. Otherwise not used.

See Section C.8.5.5.1.9 for further explanation.

>Number of Table Entries

(0018,6056)

1C

The number of entries in the Table of Pixel Values.

Required if the value of Pixel Component Organization (0018,6044) is 2 or 3.

Otherwise not used. See Section C.8.5.5.1.11 for further explanation.

>Table of Pixel Values

(0018,6058)

1C

A table of Pixel Values used in conjunction with the Table of Parameter Values (0018,605A) or Pixel Value Mapping Code Sequence (0040,9098) to provide a mapping from Pixel Value to a real world value.

Required if the Pixel Component Organization equals 2. Otherwise not used.

See Section C.8.5.5.1.12 for further explanation.

>Table of Parameter Values

(0018,605A)

1C

A table of Parameter Values used in conjunction with the Table of Pixel Values (0018,6058) to provide a mapping from Pixel Value to Parameter Value.

Required if the value of Pixel Component Organization (0018,6044) is 2.

Otherwise not used. See Section C.8.5.5.1.13 for further explanation

>Pixel Value Mapping Code Sequence

(0040,9098)

1C

Sequence that, in conjunction with the Table of Pixel Values (0018,6058), provides a mapping from a Pixel Value to an associated Coded Concept.

One or more Items shall included in this sequence. The number of Items shall be equal to the value of Number of Table Entries (0018,6056).

Required if the value of Pixel Component Organization (0018,6044) is 3 (Code Sequence look up).

See Section C.8.5.5.1.18 for further explanation.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

For IVUS Baseline CID 3497 “IVUS Arterial Morphology”; no Baseline CID is defined otherwise.

>Transducer Frequency

(0018,6030)

3

The manufacturer defined description of center frequency of the interrogating ultrasound energy. The units are kilohertz.

>Pulse Repetition Frequency

(0018,6032)

3

The ultrasound pulse repetition frequency, as defined by the manufacturer, used to collect data in the region. The units are in hertz.

>Doppler Correction Angle

(0018,6034)

3

The Doppler correction angle. The units are degrees.

>Steering Angle

(0018,6036)

3

The steering angle, as defined by the manufacturer, used for a steered 2D image. The units are degrees.

>Doppler Sample Volume X Position

(0018,6039)

3

The x displacement, in pixels, from the Reference pixel to the center of the Doppler sample volume.

>Doppler Sample Volume Y Position

(0018,603B)

3

The y displacement, in pixels, from the Reference pixel to the center of the Doppler sample volume.

>TM-Line Position x0

(0018,603D)

3

The starting and ending coordinates pairs of the m-line. Where the X0,Y0are the starting point and X1,Y1are the end point of the tm-line.

See Section C.8.5.5.1.10 for further explanation.

>TM-Line Position y0

(0018,603F)

3

The starting and ending coordinates pairs of the m-line. Where the X0,Y0are the starting point and X1,Y1are the end point of the tm-line.

See Section C.8.5.5.1.10 for further explanation.

>TM-Line Position x1

(0018,6041)

3

The starting and ending coordinates pairs of the m-line. Where the X0,Y0are the starting point and X1,Y1are the end point of the tm-line.

See Section C.8.5.5.1.10 for further explanation.

>TM-Line Position y1

(0018,6043)

3

The starting and ending coordinates pairs of the m-line. Where the X0,Y0are the starting point and X1,Y1are the end point of the tm-line.

See Section C.8.5.5.1.10 for further explanation.


C.8.5.5.1 US Region Calibration Attribute Descriptions
C.8.5.5.1.1 Region Spatial Format

Values for Region Spatial Format (0018,6012) indicate the spatial organization of the data within the region.

Enumerated Values:

0000H

None or not applicable

0001H

2D (tissue or flow)

0002H

M-Mode (tissue or flow)

0003H

Spectral (CW or PW Doppler)

0004H

Wave form (physiological traces, Doppler traces,…)

0005H

Graphics

C.8.5.5.1.2 Region Data Type

Values for Region Data Type (0018,6014) indicate the type of data within the region.

Enumerated Values:

0000H

None or not applicable

0001H

Tissue

0002H

Color Flow

0003H

PW Spectral Doppler

0004H

CW Spectral Doppler

0005H

Doppler Mean Trace

0006H

Doppler Mode Trace

0007H

Doppler Max Trace

0008H

Volume Trace

000AH

ECG Trace

000BH

Pulse Trace

000CH

Phonocardiogram Trace

000DH

Gray bar

000EH

Color bar

000FH

Integrated Backscatter

0010H

Area Trace

0011H

d(area)/dt

0012H

Other Physiological (Amplitude vs. Time) input

C.8.5.5.1.3 Region Flags

Region Flags (0018,6016) specify characteristics of US Regions.

Bit 0 of the Region Flags specifies the relative priority of the pixel component calibration specified by an US Region in the case where the US Region intersects with other US Regions. The calibration supplied by one or more of the regions may not be valid in the area that they intersect.

Enumerated Values for Bit 0 (lsb):

1

Region pixels are low priority

0

Region pixels are high priority

A high priority region overwrites data of a low priority region when they overlap, thus invalidating any pixel component calibration specified for a low priority region. pixel component calibration of overlapping regions of the same priority is indeterminate where they overlap. Figure C.8-6 shows an example of intersecting regions.

Intersecting Spatial Format Regions and Overlapping Measurement

Figure C.8-6. Intersecting Spatial Format Regions and Overlapping Measurement


In this example, Region B is Color Flow while Region A is Tissue Echo. If Region B Color Flow values share the same bit planes as Region A Tissue Echo values, then it is indeterminate whether a pixel in this region is a Color Flow pixel or a Tissue Echo pixel. Since the pixels of the Color Flow region overwrite those of the Tissue Echo region, the Region Flag of the Tissue Echo region is assigned low priority and the Region Flag of the color region is assigned high priority. This means that if both the Tissue Echo and Color Flow regions define pixel component calibration that only the calibration specified by the Color Flow region can be applied to the pixel data value at Point X.

The measurement in Figure C.8-6 is a line between Point Y and Point Z. Both points are in Region A so the distance between them can be calculated using the Region A scaling (assuming that Region A defines both the Physical Units X Direction and Y Direction as being cm). If the points are in Region B, and hence also in Region A, it is still possible to calculate the distance because the region scaling is identical in both regions. The lower priority of Region B only applies to its pixel component calibration, not its X and Y direction scaling.

Enumerated Values for Bit 1 Scaling Protection:

1

Protected

0

Not Protected

Ultrasound systems should set this to 1 if the image is scaled automatically by the ultrasound system. If the image is frame-grabbed and scaling is not available then it should be set to 0. If the region is protected, the region can not be manually rescaled. That is the data defined by the region calibration Module can not be overridden by a reader of that image.

Enumerated Values for Bit 2 Doppler Scale Type:

1

Frequency

0

Velocity

Valid for PW and CW regions only. Indicates which type of Doppler scale is used.

Enumerated Values for Bit 3-4 Scrolling Region:

00

Unspecified

01

Scrolling

10

Sweeping

11

Sweeping then Scrolling

Bit 5-31 Reserved for future use, shall be set to zero.

C.8.5.5.1.4 Pixel Component Organization

Pixel Component Organization (0018,6044) provides an Enumerated Value describing how the components of a pixel can be described. The absence of this data element means that pixel component calibration does not exist for this region.

Enumerated Values:

0

Bit aligned positions

1

Ranges

2

Table look up

3

Code Sequence look up

Other values reserved for future use.

Pixel Component Organization defines the way in which the composite pixel values are mapped into real world values with physical units, as illustrated in Figure C.8-7.

Pixel Component Calibration

Figure C.8-7. Pixel Component Calibration


An example of Component Calibration for an ultrasound image is shown in Figure C.8-8.

Pixel Component Calibration Example

Figure C.8-8. Pixel Component Calibration Example


In this example, some pixels lie within two Regions. One Region specifies pixel component calibration for Doppler velocity values. The second Region specifies pixel component calibration for Doppler magnitude. A particular Pixel Data (7FE0,0010) value will thus map to a displayed value, a Doppler velocity and magnitude value.

The example has a Palette Color Photometric Interpretation with 16 Bits Allocated and Bits Stored per sample. The Palette Color Lookup Tables also have 16 bits for each entry. The fact that the example has just one sample per pixel means that each composite pixel value is identical to the single Pixel Data value. An example Pixel Data value is shown in brackets along with the output values resulting from each step where it is processed.

The Pixel Data value is mapped to red, green, and blue values from the supplied Palette Color Lookup Tables before being displayed. The display device supports 8 bits per sample and thus requires the scaling of the output values from the 16 bit per entry LUTs.

The Doppler Velocity Region maps each pixel value in the Region to the Doppler velocity. The Pixel Component Organization (0018,6044) has a value of zero, indicating bit aligned positions with a bit mask. The Pixel Component Mask (0018,6046) specifies that the least significant 4 bits of the most significant byte convey the Doppler velocity of each pixel. The Pixel Component Physical Units (0018,604C) are cm/sec, and the Pixel Component Data Type (0018,604E) indicates color flow velocity. The Table of X Break Points (0018,6052) and Table of Y Break Points (0018,6054) map each masked composite pixel value to a Doppler velocity value in cm/sec.

The Doppler Magnitude Region maps each pixel value in the Region to the Doppler magnitude. The Pixel Component Organization (0018,6044) has a value of zero, indicating bit aligned positions with a bit mask. The Pixel Component Mask (0018,6046) specifies that the most significant 4 bits of the most significant byte convey the Doppler magnitude of each pixel. The Pixel Component Physical Units (0018,604C) is set to dB, and the Pixel Component Data Type (0018,604E) indicates color flow magnitude. The Table of X Break Points (0018,6052) and Table of Y Break Points (0018,6054) map each masked composite pixel value to a Doppler magnitude value in dB.

C.8.5.5.1.5 Pixel Component Mask

Pixel Component Mask (0018,6046) is ANDed with the Composite Pixel Code (see Section C.7.6.3.1.1) for each pixel within the region, then shifted right by the number of contiguous least significant zeros in the mask to obtain what will be referred to as the "Shifted Masked Composite Pixel Code".

The mask will most likely (but not necessarily) contain a block of contiguous ones, surrounded by leading and trailing zeros. The purpose of this mask is to keep only those bits within the composite pixel code that pertain to the region. It is to be used only when Pixel Organization is bit aligned positions.

C.8.5.5.1.6 Pixel Component Physical Units

Enumerated Values:

0000H

None or not applicable

0001H

Percent

0002H

dB

0003H

cm

0004H

seconds

0005H

hertz(seconds-1)

0006H

dB/seconds

0007H

cm/sec

0008H

cm2

0009H

cm2/sec

000AH

cm3

000BH

cm3/sec

000CH

degrees

C.8.5.5.1.7 Pixel Component Data Type

Enumerated Values:

0000H

None or not applicable

0001H

Tissue

0002H

Spectral Doppler

0003H

Color Flow Velocity

0004H

Color Flow Variance

0005H

Color Flow Intensity

0006H

Gray bar

0007H

Color bar

0008H

Integrated Backscatter

0009H

Computed Border

000AH

Tissue Classification

C.8.5.5.1.8 Number of Table Break Points

The Number of Table Break Points (0018,6050) gives the number of entries in each of two tables: the Table of X Break Points (0018,6052) and Table of Y Break Points (0018,6054). These tables are used to designate a curve mapping the value of a pixel component to its actual physical value, as described in Section C.8.5.5.1.9.

C.8.5.5.1.9 Table of X Break Points and Table of Y Break Points

Table of X Break Points (0018,6052) and Table of Y Break Points (0018,6054) are individual arrays of coordinates that interpreted together are used to create a piecewise linear curve. Each X value from the Table of X Break Points is matched with the corresponding Y value from the Table of Y Break Points yielding an (X,Y) coordinate. The set of (X,Y) coordinates describes a piecewise linear curve mapping the value of a pixel component to its actual physical value (in units defined in Pixel Component Physical Units data element (0018,604C)).

The X direction on the curve has no units, and represents actual pixel component values. If the Pixel Component Organization (0018,6044) is "Bit aligned positions", and the width of the Pixel Component Mask is n bits then the X coordinates are in the range 0 through 2n-1. If the Pixel Component Organization is Ranges, then the X coordinates are in the range 0 through 2 number of bits in the composite pixel- 1.

Note

The X value is NOT relative to the Pixel Component Range Start (0018,6048). Not all possible X values in the range need be covered by the curve.

For any pixel component value in the range of the curve described by this table, the corresponding Y value is the actual physical value for that pixel, in units specified in Pixel Component Physical Units (0018,604C). If the pixel component value is NOT within the range of specified X values for the curve, then no pixel calibration is defined by this region. It may be possible for pixel calibration to be defined by other spatial regions intersecting this one.

C.8.5.5.1.10 TM-line Position X0, Y0, X1 and Y1

The TM-Line Position X0 (0018,603D) and TM-Line Position Y0 (0018,603F) are the coordinates of the starting point and TM-Line Position X1 (0018,6041), TM-Line Position Y1 (0018,6043) are the coordinates of the end point of the TM-line. The coordinate is defined as the displacement, in pixels, from the Reference pixel. Typically used for M-mode line and CW Doppler.

C.8.5.5.1.11 Number of Table Entries

The Number of Table Entries (0018,6056) gives the number of entries in the Table of Pixel Values, the number of entries in the Table of Parameter Values (0018,605A), if present, and the number of items in the Pixel Value Mapping Code Sequence (0040,9098), if present.

C.8.5.5.1.12 Table of Pixel Values

The Table of Pixel Values (0018,6058) specifies the pixel values that are mapped to real world parameter values or coded concepts (tissue characterizations). The number of entries in the table is given by Number of Table Entries (0018,6056).

A pixel is calibrated (mapped to a real-world value) by finding an entry in the Table of Pixel Values that matches its Composite Pixel Code (see Section C.7.6.3.1.1). The offset index of this entry is used as an index into the Parameter Value Table (0018,605A) or as a sequence item number in the Pixel Value Mapping Code Sequence (0040,9098) to select the real world value. The first Table of Pixel Values entry corresponds to sequence item 1.

Note

If a Composite Pixel Code has no matching value in the Pixel Value Table then there is no unambiguous way to determine the corresponding Parameter Value. A method may exist to determine a valid Parameter Value but the specification of such a method is outside the scope of the DICOM standard. No assumption should be made that linear interpolation will produce a valid result.

C.8.5.5.1.13 Table of Parameter Values

The Table of Parameter Values (0018,605A) provides the real world values for pixel values identified in the Table of Pixel Values (0018,6058). The number of table entries is given by Number of Table Entries (0018,6056) and the physical units are given by Pixel Component Physical Units (0018,604C). Values may repeat when a parameter value is associated with more than one Composite Pixel Code value.

C.8.5.5.1.14 Region Location Min X0, Min Y0, Max X1 and Max Y1

These attributes specify the location of the region, Region Location Min X0 (0018,6018), Region Location Min Y0 (0018,601A), Region Location Max X1 (0018,601C), Region Location Max Y1 (0018,601E) expressed as offsets to the pixel coordinates. The upper left corner of the entire image is x=0,y=0 and the lower right corner is x=image width - 1, and y=image length - 1. Thus, a region will be specified as within these bounds. Where x0,y0 is the coordinate of the upper left corner of the region and x1,y1 is the coordinate of the lower right corner of the region.

C.8.5.5.1.15 Physical Units X Direction and Physical Units Y Direction

Physical Units X Direction (0018,6024) and Physical Units Y Direction (0018,6026) indicate the physical units of the dimensions of the region.

Enumerated Values:

0000H

None or not applicable

0001H

Percent

0002H

dB

0003H

cm

0004H

seconds

0005H

hertz(seconds-1)

0006H

dB/seconds

0007H

cm/sec

0008H

cm2

0009H

cm2/sec

000AH

cm3

000BH

cm3/sec

000CH

degrees

C.8.5.5.1.16 Reference Pixel X0 and Reference Pixel Y0

This coordinate pair, Reference Pixel X0 (0018,6020), Reference Pixel Y0 (0018,6022) defines the location of a virtual "reference" pixel. This reference pixel location is used to tie the image's pixel coordinate system to the physical coordinate system. For example, the reference pixel could be defined where a depth of zero centimeters occurs in the 2D image, or it could define where the baseline (i.e.,: zero frequency) resides in a spectral display. The reference pixel location is the relative offset from the Region Location Min X0 (0018,6018) and Region Location Min Y0 (0018,601A), not the image origin. The location is not required to be within the region or even within the image boundary. For this reason, the Reference Pixel X0 and Reference Pixel Y0 values can be positive or negative.

The reference pixel location varies depending on the type and spatial organization of the data within the region.

C.8.5.5.1.16.1 2D - Tissue or Color Flow

Tissue data is tissue echo intensity displayed as grayscale. The Region Data Type (0018,6014) value is 0001H (Tissue). Color flow is Doppler signal displayed as color and encoded as some function of Doppler magnitude and velocity of blood flow or tissue motion. The Region Data Type value is 0002H (Color flow). For 2D, the Region Spatial Format (0018,6012) is 0001H (2D), meaning that the region is a tomographic image. For such 2D regions the reference pixel location is typically at the center of the transducer face on the tissue-transducer interface (skin line).

Figure C.8-1 shows 2D attribute values of reference pixel location along with Region Location Min and Region Location Max. for 2D-Tissue and 2D-Color Flow Regions:

2D Regions with Reference Pixel

Figure C.8-1. 2D Regions with Reference Pixel


Both the 2D regions-Tissue and Color Flow-share the same physical location at the skin line but the reference pixel location values (Reference Pixel X0 and Reference Pixel Y0) are relative to their respective region origins at the skin line.

C.8.5.5.1.16.2 Spectral - CW or PW Doppler or Doppler Trace

Spectral Doppler is the time varying magnitude of Doppler signal as function of frequency. Region Data Type (0018,6014) value is 0003H (pulsed wave Doppler) or 0004H (continuous wave Doppler). Spectral Doppler regions display the magnitude of Doppler signal with frequency or velocity as the vertical dimension and time as the horizontal dimension. Spectral Doppler regions have a Region Spatial Format (0018,6012) of 0003H (Spectral). The time dimension for the Region Spatial Format displays horizontally with data scrolling toward the left or sweeping toward the right. The reference pixel location is the pixel in the frame where:

  • the time is the time of frame capture (i.e., the time origin for the frame)

  • and on the Doppler Baseline (i.e., where the velocity and frequency are zero).

Figure C.8-2 shows an example of reference pixel locations in an image with both a Tissue and a scrolling Spectral (CW or PW Doppler) Region. The user adjusts the depth and position of the Doppler sample volume. The system annotates the sample volume position on the 2D region and specifies the location in Doppler Sample Volume X Position (0018,6039) and Doppler Sample Volume Y Position (0018,603B).

2D & Doppler Regions with Reference Pixel

Figure C.8-2. 2D & Doppler Regions with Reference Pixel


The scrolling Spectral Region reference pixel location specifies the horizontal location at the time of the current image frame. Data to the left of this location in the Spectral Region was acquired in the past. Because time increases to the right, the Physical Delta X (0018,602C) for this Region is positive. To specify the location of the most recent data the Reference Pixel x0specifies the time of acquisition, and the Reference Pixel Physical Value X (0018,6028) specifies the reference time to be zero. The Physical Units X Direction (0018,6024) is seconds. For an explanation of how to handle sweeping regions refer to Section C.8.5.5.1.16.7 Treatment of Sweeping Regions.

The Reference Pixel Physical Value Y (0018,602A) value specifies the baseline where velocity or frequency are zero. Typically spectral Doppler regions display positive velocity (cm/Sec) or frequency shift (Hz) above the baseline. This indicates flow toward the transducer face. Negative velocity or frequency information is displayed below the baseline. This indicates flow away from the transducer face. The Physical Delta Y (0018,602E) value is therefore negative because vertical coordinates increment downward.

C.8.5.5.1.16.3 M-Mode - Tissue or Color Flow

M-Mode is tissue or color flow with a Region Spatial Format (0018,6012) of 0002H (M-mode). The vertical reference pixel location is the transducer face.

The horizontal reference pixel location is the pixel in the frame where:

  • the time is the time of frame capture (i.e., the time origin for the frame)

  • and zero depth from the transducer face

Figure C.8-3 shows an example of reference pixel locations for 2D Tissue and M-Mode Regions within the same image frame. The system annotates the sample line position on the 2D tissue region and specifies its position with the TM-Line Position attributes (0018,603D), (0018,603F), (0018,6041) and (0018,6043).

2D & M-Mode Regions with Reference Pixel Example

Figure C.8-3. 2D & M-Mode Regions with Reference Pixel Example


The physical length of the TM-Line corresponds directly to the physical height of the M-Mode Region. The M-Mode region's Reference Pixel y0 can be used to calculate the depth of the M-Mode region and facilitate depth measurements. In this example the M-Mode Region Reference Pixel y0 has a negative value corresponding to the distance between the face of the ultrasound probe and the TM-Line starting point. Note that the negative offset in pixel units is determined using the pixel height-width scaling of the M-Mode - Tissue Region as this could differ from the scaling of the 2D - Tissue Region (as it does in this example).

C.8.5.5.1.16.4 Waveform - ECG, Phonocardiogram and Pulse Traces

Waveforms are traces with a Region Spatial Format (0018,6012) value of 0004H (Waveform). The Reference Pixel x0 (0018,6020) specifies the time origin as the time of frame capture. There is typically no baseline position for ECG traces; the Reference Pixel y0 (0018,6022) is arbitrary.

Figure C.8-4 shows an example of reference pixel location for 2D Tissue, M-Mode, and ECG Waveform Regions within the same image frame:

2D, M-Mode, & Waveform Regions with Reference Pixel

Figure C.8-4. 2D, M-Mode, & Waveform Regions with Reference Pixel


C.8.5.5.1.16.5 Waveform - Doppler Mode, Mean and Max Trace

Doppler Traces have a Region Spatial Format (0018,6012) value of 0004H (Waveform) and a Region Data Type value of 0005H (Doppler Mean Trace), 0006H (Doppler Mode Trace) or 0007H (Doppler Max Trace). The Reference Pixel x0 (0018,6020) specifies the time origin as the time of frame capture. The Reference Pixel y0 (0018,6022) is the Doppler Baseline position (zero velocity / frequency position).

C.8.5.5.1.16.6 Graphics Spatial Formats

For regions with Region Spatial Format (0018,6012) value of 0005H (Graphics) the reference pixel location has no meaning.

C.8.5.5.1.16.7 Treatment of Sweeping Regions

Time-based display of data may scroll the acquired data from a fixed horizontal location to the left. Alternatively, sweep-based display increments the horizontal location of the acquired data, overwriting previously acquired data to the right. When the horizontal location corresponding to zero time has completely swept over the older data, writing wraps from the left of the region. Thus, sweep-based displays have a time discontinuity. The measurement of time intervals across the discontinuity requires special treatment. The time interval between two points across the discontinuity is equal to the region's time width minus the point separation. The sweeping area can be treated as a single region. The Reference Pixel x0 should indicate the time origin for the multi-frame image, which will be the location of the sweeping region's discontinuity line for the first frame of the multi-frame image. In order to specify that this is actually the location of the discontinuity line, the Reference Pixel Physical Value X (0018,6028) must be set to 0 seconds. This indicates that this location corresponds to the time at which the first frame was acquired.

It is useful to be able to calculate the location of the discontinuity line for subsequent frames of a multi-frame image. This is necessary if one is to determine whether two points are on opposite sides of the discontinuity line and also to correctly calculate the difference in time between such points. The x-axis location of the discontinuity line, x, for a given frame number, y, can be calculated from the Reference Pixel x0, x0, the Reference Pixel x1, x1, the time offset for frame y, t, (determined from the Frame Time Vector (0018,1065) or Frame Time (0018,1063)) and the Physical Delta X (0018,602C), px, as follows:

x = x0 + modulus((t / px) / (x1 - x0))

Alternatively, two regions can be used, one on each side of the time discontinuity. Figure C.8-5 shows the use of two regions. Note that the two region approach is not valid for multi-frame images, as the same region scaling must apply to all the frames.

Sweep Example Using Two Regions

Figure C.8-5. Sweep Example Using Two Regions


The two region approach may also be used in Doppler or physiological sweeping regions.

Time-based display of data may also be a combination of sweeping and scrolling. Sweep-based display is used at the start of acquisition, incrementing the horizontal location of the acquired data from left to right. After the horizontal location corresponding to zero time has completely swept to the right hand limit of the region, writing scrolls to the left from the right hand limit rather than wrapping from the left. A single region should be specified when this combination of behavior is used. The x-axis (zero time) location, x, for a given frame number, y, can be calculated from the Reference Pixel x0, x0, the Reference Pixel x1, x1, the time offset for frame y, t, (determined from the Frame Time Vector (0018,1065) or Frame Time (0018,1063)) and the Physical Delta X, px, as follows:

X = Min (x0 + (t / px), x1)

C.8.5.5.1.17 Physical Delta X and Physical Delta Y

The Physical Delta X (0018,602C) is the physical value increment per positive X pixel increment, which is left to right. The Physical Delta Y (0018,602E) is the physical value increment per positive Y pixel increment, which is top to bottom.

Note

When displaying Doppler data, ultrasound applications typically display the Doppler strip horizontally, with data sweeping (moving time origin) from left (oldest) to right (newest) or scrolling (static time origin) from right to left. The default display of positive velocity values normally indicates flow toward the transducer; negative velocity values indicate flow away from the transducer. In this case a negative Physical Delta Y is required to specify that the direction of positive velocities or frequencies is upward.

C.8.5.5.1.18 Pixel Value Mapping Code Sequence

The Pixel Value Mapping Code Sequence (0040,9098) provides the real world values for pixel values identified in the Table of Pixel Values (0018,6058). The number of items in the sequence is given by Number of Table Entries (0018,6056).

Note

Pixel Component Physical Units (0018,604C) does not apply to Sequence of Pixel Value Codes and should be set to 0000H (none or not applicable).

C.8.5.6 US Image Module

Table C.8-18 specifies the Attributes that describe ultrasound images.

Table C.8-18. US Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Samples Per Pixel

(0028,0002)

1

Number of samples (planes) in this image.

See Section C.8.5.6.1.12 for specialization

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data.

See Section C.8.5.6.1.2 for specialization.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample.

See Section C.8.5.6.1.13 for specialization.

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample.

See Section C.8.5.6.1.14 for specialization.

High Bit

(0028,0102)

1

Most significant bit for pixel sample data.

See Section C.8.5.6.1.15 for specialization.

Planar Configuration

(0028,0006)

1C

Indicates whether the pixel data are sent color-by-plane or color-by-pixel.

Required if Samples per Pixel (0028,0002) has a value greater than 1.

See Section C.8.5.6.1.16 for specialization.

Pixel Representation

(0028,0103)

1

Data representation of pixel samples.

See Section C.8.5.6.1.3 for specialization.

Frame Increment Pointer

(0028,0009)

1C

Contains the Data Element Tag of the attribute that is used as the frame increment in Multi-frame pixel data (see Section C.7.6.6). Required if Number of Frames is sent.

See Section C.8.5.6.1.4 for specialization.

Image Type

(0008,0008)

2

Image identification characteristics.

See Section C.8.5.6.1.1 for specialization.

Lossy Image Compression

(0028,2110)

1C

Specifies whether an Image has undergone lossy compression (at a point in its lifetime).

Enumerated Values:

00

Image has NOT been subjected to lossy compression.

01

Image has been subjected to lossy compression.

Once this value has been set to 01 it shall not be reset.

See Section C.7.6.1.1.5

Required if Lossy Compression has been performed on the Image. May be present otherwise.

Number of Stages

(0008,2124)

2C

Number of Stages in this protocol. Required if image was acquired in a Staged protocol.

Number of Views in Stage

(0008,212A)

2C

Number of views in this Stage. Required if image was acquired in a Staged protocol.

R Wave Time Vector

(0018,6060)

3

The time offset(s) of the reported R Wave peaks, each relative to the time of the start of the acquisition of the first frame in msec. Multi-valued, with one value per reported R Wave.

Ultrasound Color Data Present

(0028,0014)

3

This element indicates if any ultrasound color data is present in an image.

Enumerated Values:

00

Ultrasound color data not present in image

01

Ultrasound color data is present in image.

See Section C.8.5.6.1.10

Stage Name

(0008,2120)

3

A Stage is a particular time slice of a protocol in which a set of images are collected. The names can be free form text.

Recommended text for Stress Echo stage names:

PRE-EXERCISE

POST-EXERCISE

PEAK-EXERCISE

RECOVERY

BASELINE

LOW DOSE

PEAK DOSE

Stage Code Sequence

(0040,000A)

3

Sequence of items describing the performed Ultrasound Protocol Stage(s).

One or more Items are permitted in this Sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

Baseline CID 12002 “Ultrasound Protocol Stage Types”.

Stage Number

(0008,2122)

3

A number that identifies the Stage. Stage Number starts at one.

View Name

(0008,2127)

3

A View is a particular combination of the position and orientation when a set of images are acquired. Images are acquired at the same View in different Stages for the purpose of comparison.

View Number

(0008,2128)

3

A number that identifies the View. View Number starts at one.

Number of Event Timers

(0008,2129)

3

The number of event timers used at the time of acquisition of a Multi-frame image.

Event Elapsed Time(s)

(0008,2130)

3

An array of values associated with each event timer. Units in milliseconds.

Event Timer Name(s)

(0008,2132)

3

Name that identifies the event timer.

Include Table 10-7 “General Anatomy Optional Macro Attributes”

For intravascular ultrasound, Defined CID 3010 “Cardiovascular Anatomic Locations” and Defined CID 3015 “Coronary Arteries” are specified for the Anatomic Region Sequence and Defined CID 3019 “Cardiovascular Anatomic Location Modifiers” is specified for the Anatomic Region Modifier Sequence.

No other Context IDs are specified.

Include Table 10-25 “Optional View and Slice Progression Direction Attributes”

See Section C.8.5.6.1.19 for Context Group IDs.

Acquisition DateTime

(0008,002A)

1C

The date and time that the acquisition of data that resulted in this image started.

Required if Modality (0008,0060) = IVUS

May be present otherwise.

Note

The synchronization of this time with an external clock is specified in the Synchronization Module in Acquisition Time Synchronized (0018,1800).

Trigger Time

(0018,1060)

3

Time interval measured in msec from the start of the R-wave to the beginning of data taking

Nominal Interval

(0018,1062)

3

Average R-R interval used for these data, in msec

Beat Rejection Flag

(0018,1080)

3

Beat length sorting has been applied.

Enumerated Values:

Y

yes

N

no

Low R-R Value

(0018,1081)

3

R-R interval low limit for beat rejection, in msec

High R-R Value

(0018,1082)

3

R-R interval high limit for beat rejection, in msec

Heart Rate

(0018,1088)

3

Beats per minute.

IVUS Acquisition

(0018,3100)

1C

Defined Terms:

MOTOR_PULLBACK

MANUAL_PULLBACK

SELECTIVE

GATED_PULLBACK

See Section C.8.5.6.1.21

Required if Modality (0008,0060) = IVUS

IVUS Pullback Rate

(0018,3101)

1C

Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK. Specified in units of mm/sec.

See Section C.8.5.6.1.22

IVUS Gated Rate

(0018,3102)

1C

Required if IVUS Acquisition (0018,3100) value is GATED_PULLBACK. Specified in units of mm/beat.

See Section C.8.5.6.1.23

IVUS Pullback Start Frame Number

(0018,3103)

1C

Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK or GATED_PULLBACK.

See Section C.8.5.6.1.24

IVUS Pullback Stop Frame Number

(0018,3104)

1C

Required if IVUS Acquisition (0018,3100) value is MOTOR_PULLBACK or GATED_PULLBACK.

See Section C.8.5.6.1.25

Lesion Number

(0018,3105)

3

Identifier(s) of the lesion(s) of interest imaged within the current SOP Instance. Each lesion shall have a unique numeric integer identifier within the study.

See Section C.8.5.6.1.26.

Output Power

(0018,5000)

3

Manufacturer defined character string description of ultrasound output level(s) used in generating a given image. Data may be expressed in dB, %, W/cm2, etc.

Transducer Data

(0018,5010)

3

Manufacturer defined code or description of ultrasound transducer used.

Transducer Type

(0018,6031)

3

Defined Terms:

SECTOR_PHASED

SECTOR_MECH

SECTOR_ANNULAR

LINEAR

CURVED LINEAR

SINGLE CRYSTAL

SPLIT XTAL CWD

IV_PHASED

IV_ROT XTAL

IV_ROT MIRROR

ENDOCAV_PA

ENDOCAV_MECH

ENDOCAV_CLA

ENDOCAV_AA

ENDOCAV_LINEAR

VECTOR_PHASED

Focus Depth

(0018,5012)

3

The depth, from the transducer face, of the manufacturer defined beam focus used for the image, in cm.

Processing Function

(0018,5020)

3

Manufacturer defined description of processing of echo information. Data may include code or description of gain (initial, overall, TGC, dynamic range, etc.), preprocessing, postprocessing, Doppler processing parameters, e.g., cutoff filters, etc., as used in generating a given image.

Mechanical Index

(0018,5022)

3

See Section C.8.5.6.1.8 for Description.

Bone Thermal Index

(0018,5024)

3

See Section C.8.5.6.1.8 for Description.

Cranial Thermal Index

(0018,5026)

3

See Section C.8.5.6.1.8 for Description.

Soft Tissue Thermal Index

(0018,5027)

3

See Section C.8.5.6.1.8 for Description.

Soft Tissue-focus Thermal Index

(0018,5028)

3

See Section C.8.5.6.1.8 for Description.

Soft Tissue-surface Thermal Index

(0018,5029)

3

See Section C.8.5.6.1.8 for Description.

Depth of Scan Field

(0018,5050)

3

The depth, in mm, from the transducer face to the deepest point included in the displayed image- the field of view.

Overlay Subtype

(60xx,0045)

3

Defined Term that identifies the intended purpose of the ROI Overlay Type.

See Section C.8.5.6.1.11 for specialization.


Note

Referenced Overlay Sequence (0008,1130) and Referenced Curve Sequence (0008,1145) were previously included in this Module as optional Attributes but have been retired. See PS3.3-2004.

C.8.5.6.1 US Image Attribute Descriptions
C.8.5.6.1.1 Image Type

For US Images, Image Type (0008,0008) is specified to be Type 2.

Defined Terms for Value 3:

ABDOMINAL

BREAST

CHEST

ENDOCAVITARY

ENDORECTAL

ENDOVAGINAL

EPICARDIAL

FETAL HEART

GYNECOLOGY

INTRACARDIAC

INTRAOPERATIVE

INTRAVASCULAR

MUSCULOSKELETAL

NEONATAL HEAD

OBSTETRICAL

OPHTHALMIC

PEDIATRIC

PELVIC

RETROPERITONEAL

SCROTAL

SMALL PARTS

TEE

THYROID

TRANSCRANIAL

TTE

US BIOPSY

VASCULAR

Value 4 is constructed as a modality bit map to allow for a description of multi-modality displays. In using this bit map, the sum of the values of the various modalities will unambiguously determine the constituent modalities.

Bit Map Values for Value 4:

0001

2D Imaging

0002

M-Mode

0004

CW Doppler

0008

PW Doppler

0010

Color Doppler

0020

Color M-Mode

0040

3D Rendering

0100

Color Power Mode

0200

Tissue Characterization

0400

Spatially-related frames

Note

  1. All Values are hexadecimal encoded as a CS. See PS3.5.

  2. For example, Color Flow with CW spectral Doppler would have a value 4 = 0015. Note that no assumption should be made in Color Doppler or Color M-Mode regarding underlying B or M-Mode, respectively.

  3. See Section A.59.1 for the relationship between a 3D volume set and the 3D Rendering, 3D MPR View, and Spatially-related frames image types. In the case of "3D Rendering", Derivation Code Sequence (0008,9215) should be used to describe the specific type of 3D rendering (volume rendering, surface rendering, multiplanar reformatting, etc.).

C.8.5.6.1.2 Photometric Interpretation

Defined Terms:

MONOCHROME2

PALETTE COLOR

RGB

ARGB

(retired)

YBR_FULL

YBR_FULL_422

YBR_PARTIAL_422

YBR_RCT

YBR_ICT

YBR_PARTIAL_420

Note

It is recommended that future implementations should not use ARGB photometric interpretation.

See PS3.5 for restrictions imposed by compressed Transfer Syntaxes.

C.8.5.6.1.3 Pixel Representation

For US Images, Pixel Representation (0028,0103) is specified to use the following.

Enumerated Values:

0000H

unsigned integer

C.8.5.6.1.4 Frame Increment Pointer

For US Multi-frame images, the Attribute Frame Increment Pointer (0028,0009) of the Multi-frame Module (see Section C.7.6.6) is specified by the following.

Defined Terms:

00181063

sequencing by Frame Time (0018,1063)

00181065

sequencing by Frame Time Vector (0018,1065)

C.8.5.6.1.5 (Retired)

C.8.5.6.1.6 (Retired)

C.8.5.6.1.7 (Retired)

C.8.5.6.1.8 Mechanical Index, Bone Thermal Index, Cranial Thermal Index, Soft Tissue Thermal Index

The thermal and/or mechanical indices, when made available by a manufacturer, are defined according to the Standard for Real-Time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment, a voluntary performance standard jointly published by AIUM and NEMA.

C.8.5.6.1.9 Image Transformation Matrix and Image Translation Vector

This section was defined in a previous version of the DICOM Standard. The Section is now retired. See PS3.3-2003.

C.8.5.6.1.10 Ultrasound Color Data Present

Note

This data element can be used to indicate if an image contains any Ultrasound color data.

For example: Some Ultrasound images may have a Photometric Interpretation equal to RGB but the image will have no color information if R=G=B for all pixels.

For consistency within a particular implementation Monochrome Ultrasound images may be coded using a color photometric interpretation. In that case inclusion of this data element can significantly speed up processing. Since all components are known to be equal only one need be handled. The enhancements can be significant when compressed Transfer Syntaxes are used.

C.8.5.6.1.11 Overlay Subtype

Defined Terms:

ACTIVE 2D/BMODE IMAGE AREA

identification of the active area of a 2D/B-mode image

C.8.5.6.1.12 Samples Per Pixel

For US Images, Samples Per Pixel (0028,0002) is specified to use the following values for specific Photometric Interpretations:

Table C.8-19. US Samples Per Pixel

Photometric Interpretation

Samples Per Pixel Value

MONOCHROME2

1

RGB

3

YBR_FULL

3

YBR_FULL_422

3

YBR_PARTIAL_422

3

YBR_RCT

3

YBR_ICT

3

YBR_PARTIAL_420

3

PALETTE COLOR

1


C.8.5.6.1.13 Bits Allocated

For US Images, Bits Allocated (0028,0100) is specified to use the following values for specific Photometric Interpretations:

Table C.8-20. US Bits Allocated

Photometric Interpretation

Bits Allocated Value

MONOCHROME2

8

RGB

8

YBR_FULL

8

YBR_FULL_422

8

YBR_PARTIAL_422

8

YBR_RCT

8

YBR_ICT

8

YBR_PARTIAL_420

8

PALETTE COLOR

8 - 8 bit palette, or

16 - 16 bit palette


C.8.5.6.1.14 Bits Stored

For US Images, Bits Stored (0028,0101) is specified to use the following values for specific Photometric Interpretations:

Table C.8-21. US Bits Stored

Photometric Interpretation

Bits Stored Value

MONOCHROME2

8

RGB

8

YBR_FULL

8

YBR_FULL_422

8

YBR_PARTIAL_422

8

YBR_RCT

8

YBR_ICT

8

YBR_PARTIAL_420

8

PALETTE COLOR

8 - 8 bit palette, or

16 - 16 bit palette


C.8.5.6.1.15 High Bit

For US Images, High Bit (0028,0102) is specified to use the following values for specific Photometric Interpretations:

Table C.8-22. US High Bit

Photometric Interpretation

High Bit Value

MONOCHROME2

7

RGB

7

YBR_FULL

7

YBR_FULL_422

7

YBR_PARTIAL_422

7

YBR_RCT

7

YBR_ICT

7

YBR_PARTIAL_420

7

PALETTE COLOR

7 - 8 bit palette, or

15 - 16 bit palette


C.8.5.6.1.16 Planar Configuration

For US Images, Planar Configuration (0028,0006) is specified to use the following values for specific Photometric Interpretations:

Table C.8-23. US Planar Configuration

Photometric Interpretation

Planar Configuration Value

RGB

0 - color-by-pixel, or

1 - color-by-plane

YBR_FULL

1

YBR_FULL_422

0

YBR_PARTIAL_422

0

YBR_RCT

0

YBR_ICT

0

YBR_PARTIAL_420

0


C.8.5.6.1.19 View Code Sequence

The view of the patient anatomy may be described using coded terminology in the View Code Sequence (0054,0220). The view is typically specified by transducer position relative to the patient anatomy and/or transducer orientation,

The view may be described by a single Code Sequence Item, or by combination of post-coordinated Code Sequence Items. The principal coded item is specified in View Code Sequence, and modifier terms in the View Modifier Code Sequence (0054,0222). The Baseline CIDs for post-coordinated encoding of view are:

Any of these Context Groups may be used in either the View Code Sequence or the View Modifier Code Sequence.

For cardiac imaging, a Baseline CID with pre-coordinated view codes is specified:

Note

Transducer Position Sequence (0008,2240) and Transducer Orientation Sequence (0008,2244), defined in this module in an earlier edition of the Standard (see PS3.3-2004), are retired.

C.8.5.6.1.20 (Retired)

C.8.5.6.1.21 IVUS Acquisition

Defined Terms:

MOTOR_PULLBACK

The IVUS imaging catheter is positioned in the blood vessel under examination distal to the anatomical structures to be examined. Then the catheter is attached to a motorized mechanism capable of withdrawing the catheter through the vessel at a constant velocity specified by the attribute IVUS Pullback Rate (0018,3101) from the defined IVUS Pullback Start Frame Number (0018,3103) (see Section C.8.5.6.1.24) to the IVUS Pullback Stop Frame Number (0018,3104) (see Section C.8.5.6.1.25).

MANUAL_PULLBACK

The IVUS imaging catheter is positioned in the blood vessel under examination distal to the anatomical structures to be examined. Then the catheter is manually withdrawn through the vessel region of interest.

SELECTIVE

The IVUS imaging catheter is positioned in the blood vessel under examination near the anatomical structures to be examined. Then the catheter is manually withdrawn or advanced through the vessel region of interest.

GATED_PULLBACK

The IVUS imaging catheter is positioned in the blood vessel under examination distal to the anatomical structures to be examined. Then the catheter is attached to a motorized mechanism capable of withdrawing the catheter through the vessel at a rate specified by the attribute IVUS Gated Rate (0018,3102), once per heart cycle, from the defined IVUS Pullback Start Frame Number (0018,3103) (see Section C.8.5.6.1.24) to the IVUS Pullback Stop Frame Number (0018,3104) (see Section C.8.5.6.1.25).

C.8.5.6.1.22 IVUS Pullback Rate

The attribute IVUS Pullback Rate (0018,3101) is required when IVUS Acquisition (0018,3100) is MOTOR_PULLBACK and it specifies the velocity of withdrawal of the IVUS imaging catheter in millimeters per second.

C.8.5.6.1.23 IVUS Gated Rate

The attribute IVUS Gated Rate (0018,3102) is required when IVUS Acquisition (0018,3100) is GATED_PULLBACK and it specifies the velocity of withdrawal of the IVUS imaging catheter in millimeters per beat.

C.8.5.6.1.24 IVUS Pullback Start Frame Number

The IVUS Pullback Start Frame Number (0018,3103) specifies the frame number of a IVUS multi-frame acquisition upon which motorized or gated pullback begins.

C.8.5.6.1.25 IVUS Pullback Stop Frame Number

The IVUS Pullback Stop Frame Number (0018,3104) specifies the frame number of a IVUS multi-frame acquisition upon which motorized or gated pullback ends.

C.8.5.6.1.26 Lesion Number

Attribute Lesion Number identifies the lesion(s) of interest imaged within the current SOP Instance. Each lesion shall have a unique numeric integer identifier within the study. If during a study the same lesion is imaged more than once, the same Lesion Number should be used for both SOP Instances.

Note

  1. Lesion Number is not a DICOM UID.

  2. An IVUS pullback may contain multiple values in Lesion Number.

C.8.6 Secondary Capture Modules

C.8.6.1 SC Equipment Module

This Module describes equipment used to convert images into a DICOM format.

Table C.8-24. SC Equipment Module Attributes

Attribute Name

Tag

Type

Attribute Description

Conversion Type

(0008,0064)

1

Describes the kind of image conversion.

Defined Terms:

DV

Digitized Video

DI

Digital Interface

DF

Digitized Film

WSD

Workstation

SD

Scanned Document

SI

Scanned Image

DRW

Drawing

SYN

Synthetic Image

Modality

(0008,0060)

3

Source equipment for the image. This type definition shall override the definition in the General Series Module.

See Section C.7.3.1.1.1 for Defined Terms.

Secondary Capture Device ID

(0018,1010)

3

User defined identification of the device that converted the image

Secondary Capture Device Manufacturer

(0018,1016)

3

Manufacturer of the Secondary Capture Device

Secondary Capture Device Manufacturer's Model Name

(0018,1018)

3

Manufacturer's model number of the Secondary Capture Device

Secondary Capture Device Software Versions

(0018,1019)

3

Manufacturer's designation of software version of the Secondary Capture Device

Video Image Format Acquired

(0018,1022)

3

Original format of the captured video image (e.g., NTSC, PAL, Videomed-H)

Digital Image Format Acquired

(0018,1023)

3

Additional information about digital interface used to acquire the image


Note

  1. The Attributes specified in the General Equipment Module (see Table C.7-6) describe the equipment that created the image being captured. The Attributes of the SC Equipment Module define the equipment that captured the image. The following table illustrates typical scenarios for different conversion types:

    Conversion Type (0008,0064)

    General Equipment

    Secondary Capture Equipment

    Digitized Video (DV)

    The equipment generating the video signal.

    The equipment digitizing the video signal.

    Digital Interface (DI)

    The equipment on the sending side of the digital interface.

    The equipment on the receiving side of the digital interface.

    Digitized Film (DF)

    The equipment that created the film.

    The equipment digitizing the film.

    Workstation (WSD)

    Application dependent, but often the equipment that placed the image on the workstation screen, or created the modified image.

    The equipment that captured the image from the screen, or placed the modified image into a DICOM SOP Instance.

    Scanned Document (SD)

    The equipment that created the document.

    The equipment digitizing the document.

    Scanned Image (SI)

    The equipment that created the image that was digitized.

    The equipment digitizing the image.

    Drawing (DRW)

    The equipment that created the drawing.

    The equipment digitizing (or rasterizing) the drawing.

    Synthetic Image (SYN)

    The equipment creating the original images from which the synthetic image was derived.

    The equipment creating the synthetic image.

  2. Modality (0008,0060) specified in the General Series Module (see Table C.7-5a) has been specialized by this Module and is defined as a Type 3 Attribute.

C.8.6.2 SC Image Module

Table C.8-25 contains IOD Attributes that describe Secondary Capture Images.

Table C.8-25. SC Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Date of Secondary Capture

(0018,1012)

3

The date the Secondary Capture Image was captured.

Time of Secondary Capture

(0018,1014)

3

The time the Secondary Capture Image was captured.

Nominal Scanned Pixel Spacing

(0018,2010)

3

Physical distance on the media being digitized or scanned between the center of each pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing in mm. See Section 10.7.1.3 for further explanation of the value order.

Shall be consistent with Pixel Aspect Ratio (0028,0034), if present.

Document Class Code Sequence

(0040,E008)

3

Classifications of a scanned document, e.g., for Modality (0008,0060) DOC. Equivalent to HL7 v2.x TXA-2.

One or more items are permitted in this sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

No Baseline CID is defined.

Include Table 10-10 “Basic Pixel Spacing Calibration Macro Attributes”

Include Table 10-25 “Optional View and Slice Progression Direction Attributes”


Note

The Attributes specified in the General Image Module (see Table C.7-7) describe this image (i.e., the secondary capture image). For example, Instance Number (0020,0013) is the image number of the secondary capture image. Source Image Sequence (0008,2112) may reference the DICOM image from which this image was generated.

C.8.6.3 SC Multi-frame Image Module

Table C.8-25b contains IOD Attributes that describe SC Multi-frame images.

Table C.8-25b. SC Multi-frame Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Burned In Annotation

(0028,0301)

1

Indicates whether or not image contains sufficient burned in annotation to identify the patient and date the image was acquired.

Enumerated Values:

YES

NO

Recognizable Visual Features

(0028,0302)

3

Indicates whether or not the image contains sufficiently recognizable visual features to allow the image or a reconstruction from a set of images to identify the patient.

Enumerated Values:

YES

NO

If this Attribute is absent, then the image may or may not contain recognizable visual features.

Presentation LUT Shape

(2050,0020)

1C

Specifies an identity transformation for the Presentation LUT, such that the output of all grayscale transformations defined in the IOD containing this Module are defined to be P-Values.

Enumerated Values:

IDENTITY

Output is in P-Values.

Required if Photometric Interpretation (0028,0004) is MONOCHROME2, and Bits Stored (0028,0101) is greater than 1.

Note

If the VOI LUT Module is required by the IOD but no VOI LUT Sequence (0028,3010) or Window Center (0028,1050) is present, then the VOI LUT stage is an identity transformation.

Illumination

(2010,015E)

3

Luminance of a hypothetical viewing device illuminating a piece of monochrome transmissive film, or for the case of reflective media, luminance obtainable from diffuse reflection of the illumination present. Expressed as L0, in candelas per square meter (cd/m2).

Note

May be used together with Reflected Ambient Light (2010,0160) to recover Optical Density information from P-Values. See Section C.8.6.3.1.

Reflected Ambient Light

(2010,0160)

3

For scanned monochrome transmissive film viewed on a hypothetical viewing device, the luminance contribution due to reflected ambient light. Expressed as La, in candelas per square meter (cd/m2).

Note

May be used together with Illumination (2010,015E) to recover Optical Density information from P-Values. See Section C.8.6.3.1.

Rescale Intercept

(0028,1052)

1C

The value b in the relationship between stored values (SV) in Pixel Data (7FE0,0010) and the output units specified in Rescale Type (0028,1054).

Output units = m*SV + b.

Required if Photometric Interpretation (0028,0004) is MONOCHROME2, and Bits Stored (0028,0101) is greater than 1.

Note

This specifies an identity Modality LUT transformation.

Rescale Slope

(0028,1053)

1C

m in the equation specified by Rescale Intercept (0028,1052).

Required if Photometric Interpretation (0028,0004) is MONOCHROME2, and Bits Stored (0028,0101) is greater than 1.

Note

This specifies an identity Modality LUT transformation.

Rescale Type

(0028,1054)

1C

Specifies the output units of Rescale Slope (0028,1053) and Rescale Intercept (0028,1052).

Defined Terms:

US

Unspecified

Required if Photometric Interpretation (0028,0004) is MONOCHROME2, and Bits Stored (0028,0101) is greater than 1.

Note

This specifies an identity Modality LUT transformation.

Frame Increment Pointer

(0028,0009)

1C

Contains the Data Element Tag of the attribute that is used as the frame increment in Multi-frame pixel data. See Section C.7.6.6.1.2 for further explanation.

Shall be present if Number of Frames is greater than 1, overriding (specializing) the Type 1 requirement on this attribute in the Multi-frame Module.

Nominal Scanned Pixel Spacing

(0018,2010)

1C

Physical distance on the media being digitized or scanned between the center of each pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing in mm. See Section 10.7.1.3 for further explanation of the value order.

Required if Conversion Type (0008,0064) is DF (Digitized Film). May also be present if Conversion Type (0008,0064) is SD (Scanned Document) or SI (Scanned Image).

Shall be consistent with Pixel Aspect Ratio (0028,0034), if present.

Include Table 10-10 “Basic Pixel Spacing Calibration Macro Attributes”

Digitizing Device Transport Direction

(0018,2020)

3

Enumerated Values:

ROW

COLUMN

Rotation of Scanned Film

(0018,2030)

3

Angle of the edge of the film relative to the transport direction in degrees greater than or equal to -45 and less than or equal to +45.


C.8.6.3.1 Scanned Film, Optical Density and P-Values

Illumination (2010,015E) and Reflected Ambient Light (2010,0160) may be used to recover Optical Density information from P-Values.

Monochrome media that is being digitized is often measured in Optical Density values. These values need to be converted to P-Values for storage and display. The P-Values used in an image correspond to the perception of a human observer viewing the film on a hypothetical viewing device (such as a light box), using the specified values of Illumination (2010,015E) and Reflected Ambient Light (2010,0160).

The Grayscale Standard Display Function defined in PS3.14 is used to convert Luminance to P-Values. In the case of scanned film, the Luminance is derived from Optical Density using the specified values of Illumination (2010,015E) and Reflected Ambient Light (2010,0160). An example of this derivation, as well as typical "default" values for these parameters, is specified in PS3.14.

C.8.6.4 SC Multi-frame Vector Module

Table C.8-25c contains IOD Attributes that may be the target of the Frame Increment Pointer (0028,0009) for SC Multi-frame images.

Table C.8-25c. SC Multi-frame Vector Module Attributes

Attribute Name

Tag

Type

Attribute Description

Frame Time Vector

(0018,1065)

1C

An array that contains the real time increments (in msec) between frames for a Multi-frame image.

See Section C.7.6.5.1.2 for further explanation.

Required if Frame Increment Pointer (0028,0009) points to Frame Time Vector (0018,1065).

Note

Frame Time Vector arrays may not be properly encoded if Explicit VR transfer syntax is used and the VL of this attribute exceeds 65534 bytes.

Page Number Vector

(0018,2001)

1C

An array that contains, for each of the image frames, the corresponding page numbers of the original document.

Required if Frame Increment Pointer (0028,0009) points to Page Number Vector (0018,2001).

Frame Label Vector

(0018,2002)

1C

An array that contains, for each of the image frames, a descriptive label.

Required if Frame Increment Pointer (0028,0009) points to Frame Label Vector (0018,2002).

Frame Primary Angle Vector

(0018,2003)

1C

An array that contains, for each of the image frames, the primary angle of rotation about an undefined axis, in degrees. May be used for annotative purposes for "cine loops" of 3D reprojected images

Required if Frame Increment Pointer (0028,0009) points to Frame Primary Angle Vector (0018,2003).

Frame Secondary Angle Vector

(0018,2004)

1C

An array that contains, for each of the image frames, the secondary angle of rotation about an undefined axis that is orthogonal to that used for Frame Primary Angle Vector (0018,2003), in degrees. May be used for annotative purposes for "cine loops" of 3D reprojected images

Required if Frame Increment Pointer (0028,0009) points to Frame Secondary Angle Vector (0018,2004).

Slice Location Vector

(0018,2005)

1C

An array that contains, for each of the image frames, the relative position of the image plane expressed in mm, as defined for Slice Location (0020,1041). See Section C.7.6.2.1.2 for further explanation.

Required if Frame Increment Pointer (0028,0009) points to Slice Location Vector (0018,2005).

Display Window Label Vector

(0018,2006)

1C

An array that contains, for each of the image frames, a label or number of the display window of a graphical user interface from which the frame was captured.

Required if Frame Increment Pointer (0028,0009) points to Display Window Label Vector (0018,2006).


C.8.7 X-Ray Modules

This Section describes Modules used in one or more X-Ray IODs. These Modules contain Attributes that are specific to X-Ray images.

C.8.7.1 X-Ray Image Module

Table C.8-26. X-Ray Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Frame Increment Pointer

(0028,0009)

1C

Required if Multi-frame Image.

Contains the Data Element Tag of the attribute that is used as the Frame increment in Multi-frame image pixel data (see Section C.7.6.6).

Enumerated Values:

00181063H

Frame Time (0018,1063)

00181065H

Frame Time Vector (0018,1065)

Lossy Image Compression

(0028,2110)

1C

Specifies whether an Image has undergone lossy compression (at a point in its lifetime).

Enumerated Values:

00

Image has NOT been subjected to lossy compression.

01

Image has been subjected to lossy compression.

Once this value has been set to 01 it shall not be reset.

See Section C.7.6.1.1.5

Required if Lossy Compression has been performed on the Image. May be present otherwise.

Image Type

(0008,0008)

1

Image identification characteristics.

See Section C.8.7.1.1.1 for specialization.

Pixel Intensity Relationship

(0028,1040)

1

The relationship between the Pixel sample values and the X-Ray beam intensity.

See Section C.8.7.1.1.2.

Samples per Pixel

(0028,0002)

1

Number of samples (color planes) in this image shall have a value of 1.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data. Only MONOCHROME2 may be used.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample.

See Section C.8.7.1.1.6.

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample.

See Section C.8.7.1.1.7.

High Bit

(0028,0102)

1

Most significant bit for pixel sample data.

See Section C.8.7.1.1.8.

Pixel Representation

(0028,0103)

1

Data representation of the pixel samples.

Shall have the value:

0000H = Unsigned Integer.

Scan Options

(0018,0022)

3

Parameters of scanning sequence.

See Section C.8.7.1.1.4.

Include Table 10-7 “General Anatomy Optional Macro Attributes”

No Context ID for the Anatomic Region Sequence is defined.

R Wave Pointer

(0028,6040)

3

Marks the location(s) of the R Wave in the cardiac cycles by referencing frame numbers; frame numbers begin with 1.

Referenced Image Sequence

(0008,1140)

1C

Other images significantly related to this image. Shall be present if Image Type (0008,0008) Value 3 is BIPLANE A or BIPLANE B. May be present otherwise.

One or more items shall be included in this sequence.

See Section C.8.7.1.1.13.

>Include Table 10-3 “Image SOP Instance Reference Macro Attributes”

>Purpose of Reference Code Sequence

(0040,A170)

3

Describes the purpose for which the reference is made.

Only a single Item is permitted in this Sequence.

>>Include Table 8.8-1 “Code Sequence Macro Attributes”

Defined CID 7201 “Referenced Image Purposes of Reference”.

Derivation Description

(0008,2111)

3

A text description of how this image was derived.

See Section C.8.7.1.1.5 for further explanation.

Acquisition Device Processing Description

(0018,1400)

3

Indicates any visual processing performed on the images prior to exchange.

See Section C.8.7.1.1.3.

Frame Label Vector

(0018,2002)

3

A multi-valued attribute that contains a descriptive label for each of the image frames. The number of values shall equal the number of frames.

Frame Dimension Pointer

(0028,000A)

3

Contains the Data Element Tags of one or more attributes that vary or increment for the frames of a multi-frame image. See Section C.8.7.1.1.12.

Shall not be present if it would contain only one value and that value would be Frame Time (0018,1063) or Frame Time Vector (0018,1065).

Calibration Image

(0050,0004)

3

Indicates whether a reference object (phantom) of known size is present in the image and was used for calibration.

Enumerated Values:

YES

NO

Device is identified using the Device module. See Section C.7.6.12.


C.8.7.1.1 X-Ray Image Attribute Descriptions
C.8.7.1.1.1 Image Type

The Image Type attribute identifies important image characteristics in a multiple valued data element. For X-Ray, Image Type is specialized as follows:

  • Value 1 shall identify the Pixel Data Characteristics in accordance with Section C.7.6.1.1.2

    Enumerated Values:

    ORIGINAL

    DERIVED

    Note

    X-Ray images generally use PRIMARY value for images captured from patient exposure.

  • Value 2 shall identify the Patient Examination Characteristics in accordance with Section C.7.6.1.1.2

    Enumerated Values:

    PRIMARY

    SECONDARY

  • Value 3 shall identify the image set in terms of the imaging planes.

    Enumerated Values:

    SINGLE PLANE

    Image is a single plane acquisition

    BIPLANE A

    Image is the first plane (e.g., Frontal) of a Bi-plane acquisition

    BIPLANE B

    Image is the second plane (e.g., Lateral) of a Bi-plane acquisition

  • Other Values are implementation specific (optional).

C.8.7.1.1.2 Pixel Intensity Relationship

Pixel Intensity Relationship (0028,1040) shall identify the relationship of the pixel values to the X-Ray beam intensity.

Defined Terms:

LIN

Approximately proportional to X-Ray beam intensity;

LOG

Non-linear "Log Function"; A Modality LUT shall be included with the image to allow it to be scaled back to its proportional value to X-Ray beam intensity;

DISP

Ready to be displayed; A Modality LUT may be included with the image to allow it to be scaled back to its proportional value to X-Ray beam intensity. The Attribute Acquisition Device Processing Description may be used to provide some indication on the pre-processing performed to create the ready to be displayed image.

C.8.7.1.1.3 Acquisition Device Processing Description

Acquisition Device Processing Description (0018,1400) provides some indication in human readable text of the digital processing on the images before exchange. Examples of this processing are: edge enhanced, subtracted, time filtered, gamma corrected, convolved (spatially filtered).

C.8.7.1.1.4 Scan Options

The Scan Options attribute identifies any acquisition technique that was used during the acquisition of the image.

Defined Terms:

EKG

EKG Event Trigger

PHY

Physiological Event Trigger

TOMO

Tomography

CHASE

Bolus Chasing

ROTA

Rotation

C.8.7.1.1.5 Derivation Description

If an Image is identified to be a Derived image (see Section C.8.7.1.1.1), Derivation Description (0008,2111) is an optional and implementation specific text description of the way the image was derived from an original image. As applied to X-Ray images, it may be used to describe derivation operations such as edge enhancement, temporal filtering, digital subtraction, or other linear and non-linear transformations.

C.8.7.1.1.6 Bits Allocated

Enumerated Values:

8

16

C.8.7.1.1.7 Bits Stored

Enumerated Values:

8

10

12

16

C.8.7.1.1.8 High Bit

For X-Ray Images, High Bit (0028,0102) shall be one less than the value in Bit Stored.

C.8.7.1.1.9 Synchronization of Frame and Waveform Times

The synchronization of a multi-frame X-Ray image with a waveform (e.g., ECG, pressure, or respiration) encoded in a different SOP Instance is managed through the attributes of the Synchronization Module (see Section C.7.4.2) of the Frame of Reference IE.

Note

The use of a Curve IE within the X-Ray IODs was previously defined in DICOM (see PS3.3-2004). That use has been retired in favor of encoding waveform data in a separate IOD.

C.8.7.1.1.12 Frame Dimension Pointer

Frame Dimension Pointer (0028,000A) identifies attributes that vary or increment with each frame, and are clinically significant for viewing or processing the image. This is intended for SOP Instances whose preferred clinical presentation is dependent on frame relationships other than simply time.

Defined Terms for multi-frame cine from the Cine Module (see Section C.7.6.5) are:

00181063H

Frame Time (0018,1063)

00181065H

Frame Time Vector (0018,1065)

Defined Terms for rotational acquisition from the XA Positioner Module (see Section C.8.7.5) are:

00181520H

Positioner Primary Angle Increment (0018,1520)

00181521H

Positioner Secondary Angle Increment (0018,1521)

Defined Terms for stepped acquisition from the X-Ray Table Module (see Section C.8.7.4) are:

00181135H

Table Vertical Increment (0018,1135)

00181137H

Table Longitudinal Increment (0018,1137)

00181136H

Table Lateral Increment (0018,1136)

Defined Terms for an arbitrary labeled increment:

00182002H

Frame Label Vector (0018,2002)

Note

  1. Previous editions of the standard did not include the optional Frame Dimension Pointer (0028,000A), but instead depended entirely on the mandatory Frame Increment Pointer (0028,0009), and envisaged that only time and no other dimension would relate frames. Image creators that add the Frame Dimension Pointer (0028,000A) must anticipate that many implementations will ignore or discard this attribute when displaying or storing images and continue to assume that frames are temporally related.

  2. Frame Time (0018,1063) or Frame Time Vector (0018,1065) will also be present and will contain appropriate values consistent with the times of acquisition of the frames.

C.8.7.1.1.13 Referenced Image Sequence

When Image Type (0008,0008) Value 3 is BIPLANE A or BIPLANE B, Referenced Image Sequence (0008,1140) shall be used to identify the corresponding SOP Instance of the Biplane acquisition. In this case, either:

  • only a single item shall be present, or

  • multiple items may be present, each with the Purpose of Reference Code Sequence (0040,A170) present, and only the first item having the Purpose of Reference value (121314, DCM, "Other image of biplane pair").

The Referenced Frame Number (0008,1160) attribute shall not be present in the Item that references the corresponding SOP Instance of the Biplane acquisition.

C.8.7.2 X-Ray Acquisition Module

Table C.8-27. X-Ray Acquisition Module Attributes

Attribute Name

Tag

Type

Attribute Description

KVP

(0018,0060)

2

Peak kilo voltage output of the X-Ray generator used.

Radiation Setting

(0018,1155)

1

Identify the general level of X-Ray dose exposure.

Enumerated Values:

SC

low dose exposure generally corresponding to fluoroscopic settings (e.g., preparation for diagnostic quality image acquisition)

GR

high dose for diagnostic quality image acquisition (also called digital spot or cine)

X-Ray Tube Current

(0018,1151)

2C

X-Ray Tube Current in mA. Required if Exposure (0018,1152) is not present. May be present otherwise.

X-Ray Tube Current in µA

(0018,8151)

3

X-Ray Tube Current in µA.

Exposure Time

(0018,1150)

2C

Duration of X-Ray exposure in msec. See 8.7.2.1.1. Required if Exposure (0018,1152) is not present. May be present otherwise.

Exposure Time in µS

(0018,8150)

3

Duration of X-Ray exposure in µsec.

Exposure

(0018,1152)

2C

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current. Required if either Exposure Time (0018,1150) or X-Ray Tube Current (0018,1151) are not present. May be present otherwise.

Exposure in mAs

(0018,9332)

3

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current.

Grid

(0018,1166)

3

Identify the grid. Only a single value shall be present.

Defined Terms:

IN

A Grid is positioned;

NONE

No Grid is used.

Average Pulse Width

(0018,1154)

3

Average width of X-Ray pulse in msec.

Radiation Mode

(0018,115A)

3

Specifies X-Ray radiation mode.

Defined Terms:

CONTINUOUS

PULSED

Type of Filters

(0018,1161)

3

Type of filter(s) inserted into the X-Ray beam (e.g., wedges).

Intensifier Size

(0018,1162)

3

Diameter of X-Ray intensifier in mm

Field of View Shape

(0018,1147)

3

Shape of the Image Intensifier Field of View. See Section C.8.7.2.1.2.

Defined Terms:

ROUND

RECTANGLE

Field of View Dimension(s)

(0018,1149)

3

Dimensions of the Image Intensifier Field of View in mm. If Rectangle, row dimension followed by column; if Round, diameter.

Imager Pixel Spacing

(0018,1164)

3

Physical distance measured at the front plane of the Image Receptor housing between the center of each pixel specified by a numeric pair - row spacing value(delimiter) column spacing value in mm. See Section 10.7.1.3 for further explanation of the value order.

The value of this attribute shall never be adjusted to account for correction for the effect of geometric magnification or calibration against an object of known size; Pixel Spacing (0028,0030) is specified for that purpose.

Include Table 10-10 “Basic Pixel Spacing Calibration Macro Attributes”

Focal Spot(s)

(0018,1190)

3

Nominal focal spot size in mm used to acquire this image.

Image and Fluoroscopy Area Dose Product

(0018,115E)

3

X-Ray dose, measured in dGy*cm*cm, to which the patient was exposed for the acquisition of this image plus any non-digitally recorded fluoroscopy that may have been performed to prepare for the acquisition of this image.

Note

The sum of the area dose product of all images of a Series or a Study may not result in the total area dose product to which the patient was exposed.


C.8.7.2.1 X-Ray Acquisition Attribute Descriptions
C.8.7.2.1.1 Exposure Time

Exposure time is the cumulative time the patient received X-Ray exposure during this image (Multi-frame image acquisition). Calculation is pulse width * number of frames.

C.8.7.2.1.2 Field of View

The Field of View Attribute describes the shape and dimensions of the Image Receptor Field of View, applicable to both Image Intensifier and Digital Detector. This could be further restricted by the Collimator. See Section C.8.7.3.

C.8.7.3 X-Ray Collimator

An X-Ray Collimator is a device placed close to the X-Ray Source to restrict the span of the X-Ray beam. It is often made of lead shutters. Figure C.8-9 presents in a graphical form its relationship with the Field Of View Dimensions (0018,1149).

Geometry of the collimator is specified with respect to a row and column coordinate system where the origin is the upper left hand pixel. This origin is specified by the values 1,1 for row/column. A row coordinate represent a number of raw spacing (vertical) and a column coordinate represents a column spacing (horizontal). Up to three different collimator shapes may be used and superimposed.

Relationships of X-Ray Collimator

Figure C.8-9. Relationships of X-Ray Collimator


Table C.8-28. X-Ray Collimator Module Attributes

Attribute Name

Tag

Type

Attribute Description

Collimator Shape

(0018,1700)

1

Shape(s) of the collimator.

Enumerated Values:

RECTANGULAR

CIRCULAR

POLYGONAL

This multi-valued Attribute shall contain at most one of each Enumerated Value.

Include Table C.8-28b “X-Ray Collimator Dimensions Macro Attributes”


Table C.8-28b. X-Ray Collimator Dimensions Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Collimator Left Vertical Edge

(0018,1702)

1C

Required if a value of Collimator Shape (0018,1700) is RECTANGULAR. Location of the left edge of the rectangular collimator with respect to pixels in the image given as column. See Section C.8.7.3.1.1.

Collimator Right Vertical Edge

(0018,1704)

1C

Required if a value of Collimator Shape (0018,1700) is RECTANGULAR. Location of the right edge of the rectangular collimator with respect to pixels in the image given as column. See Section C.8.7.3.1.1.

Collimator Upper Horizontal Edge

(0018,1706)

1C

Required if a value of Collimator Shape (0018,1700) is RECTANGULAR. Location of the upper edge of the rectangular collimator with respect to pixels in the image given as row. See Section C.8.7.3.1.1.

Collimator Lower Horizontal Edge

(0018,1708)

1C

Required if a value of Collimator Shape (0018,1700) is RECTANGULAR. Location of the lower edge of the rectangular collimator with respect to pixels in the image given as row. See Section C.8.7.3.1.1.

Center of Circular Collimator

(0018,1710)

1C

Required if a value of Collimator Shape (0018,1700) is CIRCULAR. Location of the center of the circular collimator with respect to pixels in the image given as row and column. See Section C.8.7.3.1.1.

Radius of Circular Collimator

(0018,1712)

1C

Required if a value of Collimator Shape (0018,1700) is CIRCULAR. Radius of the circular collimator with respect to pixels in the image given as a number of pixels along the row direction. See Section C.8.7.3.1.1.

Vertices of the Polygonal Collimator

(0018,1720)

1C

Required if a value of Collimator Shape (0018,1700) is POLYGONAL.

Multiple Values where the first set of two values are:

row of the origin vertex;

column of the origin vertex.

Two or more pairs of values follow and are the row and column coordinates of the other vertices of the polygon collimator. Polygon collimators are implicitly closed from the last vertex to the origin vertex and all edges shall be non-intersecting except at the vertices.


C.8.7.3.1 X-Ray Collimator Attribute Descriptions
C.8.7.3.1.1 Collimator Vertical and Horizontal Edges

These attributes specify the pixel row or column where the X-Ray beam is fully obscured by a rectangular collimator:

  • if the left edge of the collimator is not visible, Collimator Left Vertical Edge (0018,1702) shall have a value of 0;

  • if the right edge of the collimator is not visible, Collimator Right Vertical Edge (0018,1704) value shall be 1 greater than the value of Columns (0028,0011) attribute;

  • if the top edge of the collimator is not visible, Collimator Upper Horizontal Edge (0018,1706) shall have a value of 0;

  • if the bottom edge of the collimator is not visible, Collimator Lower Horizontal Edge (0018,1708) value shall be 1 greater than the value of Rows (0028,0010) attribute.

C.8.7.4 X-Ray Table Module

Table C.8-29 contains Attributes that describe X-Ray images acquired with movement of the patient imaging table.

Table C.8-29. X-Ray Table Module Attributes

Attribute Name

Tag

Type

Attribute Description

Table Motion

(0018,1134)

2

Defined Terms:

STATIC

DYNAMIC

Table Vertical Increment

(0018,1135)

2C

Incremental change in Vertical position of the table relative to first frame of Multi-frame image given in mm.

Required if Table Motion is DYNAMIC.

Table Longitudinal Increment

(0018,1137)

2C

Incremental change in Longitudinal position of the table relative to first frame of Multi-frame image in mm. Table motion towards +90°position of the primary angle of the positioner is positive. See Section C.8.7.4.1.2.

Required if Table Motion is DYNAMIC.

Table Lateral Increment

(0018,1136)

2C

Incremental change in Lateral position of the table relative to first frame of Multi-frame image given in mm. Table motion towards +90°position of the secondary angle of the positioner is positive. See Section C.8.7.4.1.3.

Required if Table Motion is DYNAMIC.

Table Angle

(0018,1138)

3

Angle of table plane in degrees relative to horizontal plane [Gravity plane]. Positive values indicate that the head of the table is upwards.


C.8.7.4.1 X-Ray Table Attribute Descriptions
C.8.7.4.1.1 Table Motion Increments

This section is replaced by Section C.8.7.4.1.4

C.8.7.4.1.2 Table Longitudinal Increment

The direction of the longitudinal movement is perpendicular to the primary axis of rotation of the positioner. A positive value of Table Longitudinal Increment (0018,1137) attributes indicates a movement towards the +90° position of the positioner, see Figure C.8-9a.

Table Longitudinal Movement

Figure C.8-9a. Table Longitudinal Movement


C.8.7.4.1.3 Table Lateral Increment

The direction of the lateral movement is perpendicular to the secondary axis of rotation of the positioner. A positive value of Table Lateral Increment (0018,1136) attributes indicates a movement towards the +90° position of the positioner, see Figure C.8-9b.

Table Lateral Movement

Figure C.8-9b. Table Lateral Movement


Note

The terms "longitudinal" and "lateral" are relative to an operator standing tableside, and facing the patient. Thus lateral movement is to the left and right of the operator, and longitudinal movement is towards or away from the operator.

C.8.7.4.1.4 Table Motion With Patient in Relation to Imaging Chain

The table moves the Patient with respect to the imaging chain. This is being tracked as a motion of the imaging chain with respect to a coordinate system (X, Y, Z) attached to the patient (assumption is that the patient does not move with respect to the table). The coordinate system origin is fixed with respect to the patient at the time of the first frame. The X-axis is increasing to the left hand side of the patient. The Y-axis is increasing to the posterior side of the patient. The Z-axis is increasing toward the head of the patient (see Section C.7.6.2.1.1). The Patient Plane is then defined by the X and Z-axes as drawn in Figure C.8-10).

Note

  1. Table motion causes the apparent locus of imaging to move in the opposite direction. For instance, with the patient supine and the table motion towards +90°of the primary axis of rotation of the positioner, the area of the patient imaged moves toward the right hand side of the patient.

  2. When the patient is positioned prone or supine (Figure C.8-2 showing the supine position) the Table Longitudinal Increment (0018,1137) table motion takes place along the patient X-axis and the Table Lateral Increment (0018,0036) along the Z-axis. For patient positioned left or right decubitus, the Table Longitudinal Increment takes place along the Y-axis, the other direction is not changed.

Table Motion Vector Coordinates

Figure C.8-10. Table Motion Vector Coordinates


C.8.7.5 XA Positioner Module

Table C.8-30 contains IOD Attributes that describe a c-arm positioner typically used in acquiring X-Ray Angiographic Images. The coordinate system used to track the positioner is defined in reference to the patient. The definition of coordinates with respect to the equipment is not supported. Furthermore, this module does not describe the movement of the Patient.

Note

The scope of the XA IOD is to address images produced on acquisition equipment equipped with an X-Ray source and an image Receptor positioned by what is general called a c-arm. For clinical areas other than Angiography that are using a c-arm to position the X-Ray source and image receptor (e.g., Interventional Procedures and Myelography and Biopsy/Localization), the X-Ray Angiography Image Object should be also used. Although the object is optimized for c-arm systems, it may also be used by other systems that support a similar coordinate system, such as some RF systems.

Table C.8-30. XA Positioner Module Attributes

Attribute Name

Tag

Type

Attribute Description

Distance Source to Patient

(0018,1111)

3

Distance in mm from source to center of field of view.

Note

  1. This value is traditionally referred to as Source Object Distance (SOD).

  2. For cardiovascular image equipment the SOD value typically is the distance from source to isocenter.

Distance Source to Detector

(0018,1110)

3

Distance in mm from source to detector center.

Note

This value is traditionally referred to as Source Image Receptor Distance (SID).

Estimated Radiographic Magnification Factor

(0018,1114)

3

Ratio of Source Image Receptor Distance (SID) over Source Object Distance (SOD).

Positioner Motion

(0018,1500)

2C

Used to describe the activity of the imaging devices.

Defined Terms:

DYNAMIC

STATIC

See Section C.8.7.5.1.1.

Required if Pixel Data (7FE0,0010) contains more than one frame. May be present otherwise.

Positioner Primary Angle

(0018,1510)

2

Position of the X-Ray Image Intensifier about the patient from the RAO to LAO direction where movement from RAO to vertical is positive.

See Section C.8.7.5.1.2.

Positioner Secondary Angle

(0018,1511)

2

Position of the X-Ray Image Intensifier about the patient from the CAU to CRA direction where movement from CAU to vertical is positive.

See Section C.8.7.5.1.2

Positioner Primary Angle Increment

(0018,1520)

2C

Incremental change in primary positioner angle for each frame.

See Section C.8.7.5.1.3.

Required if Positioner Motion (0018,1500) equals DYNAMIC.

Positioner Secondary Angle Increment

(0018,1521)

2C

Incremental change in secondary positioner angle for each frame.

See Section C.8.7.5.1.3.

Required if Positioner Motion (0018,1500) equals DYNAMIC.

Detector Primary Angle

(0018,1530)

3

Angle of the X-Ray beam in the row direction in degrees relative to the normal to the detector plane. Positive values indicate that the X-Ray beam is tilted towards higher numbered columns. Negative values indicate that the X-Ray beam is tilted towards lower numbered columns.

See Section C.8.7.5.1.4.

Detector Secondary Angle

(0018,1531)

3

Angle of the X-Ray beam in the column direction in degrees relative to the normal to the detector plane. Positive values indicate that the X-Ray beam is tilted towards lower numbered rows. Negative values indicate that the X-Ray beam is tilted towards higher numbered rows.

See Section C.8.7.5.1.4.


C.8.7.5.1 XA Positioner Attribute Descriptions
C.8.7.5.1.1 Positioner Motion

Positioner Motion (0018,1500) attribute is STATIC if the imaging table moves during a multi-frame acquisition, but the X-Ray positioner do not move.

If Pixel Data (7FE0,0010) contains a single frame and a value of Positioner Motion (0018,1500) is provided, the value shall be STATIC.

Note

If the positioner undergoes translation (non-rotational movement) during the acquisition, then that motion shall be described by an opposite table motion (see Section C.8.7.4).

C.8.7.5.1.2 Positioner Primary and Secondary Angles

The definitions of Positioner Angles shall be with respect to the patient as illustrated in Figure C.8-11 and Figure C.8-12. Zero degree is referenced to the origin perpendicular to the patient's chest. The Positioner Primary Angle definition is like longitude (in the equatorial plan); the Positioner Secondary Angle definition is like latitude (in the sagittal plane). The Positioner Angle attributes apply to the first frame of a multi-frame image. The valid range of Primary Positioner Angle is -180 to +180 degrees and the Secondary Positioner Angle range is -90 to + 90 degrees.

The Patient Plane is defined by the isocenter of the imaging device and slices through the patient such that it is perpendicular to the sagittal plane of the body. The Primary Axis of rotation is defined at the intersection of the Patient Plane and of the Sagittal Plane. The Positioner Primary Angle is defined in the transaxial plane at the isocenter with zero degrees in the direction perpendicular to the patient's chest and + 90 degrees at the Patient left hand side (LAO) and -90 at the Patient right hand side (RAO). The valid range of Primary Positioner Angle is -180 to +180 degrees.

The Secondary Axis is in the Patient Plane and is perpendicular to the Primary Axis at the isocenter. The Positioner Secondary Angle is defined in the Sagittal Plane at the isocenter with zero degrees in the direction perpendicular to the patient's chest. +90 degrees corresponds to the cranial direction. The Secondary Positioner Angle range is -90 to + 90 degrees.

At a 0 angle for both Primary Angle (0018,1510) and Secondary Angle (0018,1511), the patient faces the Image Intensifier.

The Positioner Primary Angle (0018,1510) and Secondary Angle (0018,1511) apply to the first frame of a multi-frame image.

Positioner Primary Angle

Figure C.8-11. Positioner Primary Angle


Positioner Secondary Angle

Figure C.8-12. Positioner Secondary Angle


C.8.7.5.1.3 Positioner Angle Increments

If the positioner angles change during acquisition of a multi-frame image, the Positioner Angle Increment attributes describe the angular change per frame.

If the change in positioner angle is nominally constant for each frame, these fields may contain a single value of the average angular change per frame. Alternatively, the fields may contain a vector of offsets from the (initial) Positioner Angle attributes, with one value for each frame in the multi-frame image. The number of values in the Positioner Angle Increment attributes must be one, or must be equal to Number of Frames (0028,0008) in the Multi-frame Module (see Section C.7.6.6).

Note

It is permissible to generate a vector of the absolute positioner angles in the Positioner Angle Increment attributes, and set the Positioner Primary and Secondary Angle attributes to value 0.

C.8.7.5.1.4 Detector Primary and Secondary Angles

Detector Angles are defined in a fashion similar to the positioner angles, except that the angle of the central x-ray beam vector is relative to the detector plane rather than the patient plane. The central x-ray beam vector is defined as the vector from the x-ray source through the isocenter to the detector plane. Zero degree is referenced to the normal to the detector plane pointing away from the x-ray source. The Detector Angle attributes apply to the first frame of a multi-frame image. The valid range of the Detector Angles is -90 to + 90 degrees.

The Primary Axis of rotation is defined along the line in the column direction of the detector plane that intersects the central x-ray beam vector. The Detector Primary Angle is defined in the plane perpendicular to the Primary Axis of rotation at the point where the central x-ray beam vector intersects the detector plane, with zero degrees in the direction normal to the detector plane and -90 degrees at the left hand side of the image (i.e., toward column 1) and +90 at the right hand side of the image (i.e., toward the highest numbered column). The valid range of Primary Detector Angle is -90 to +90 degrees.

The Secondary Axis is in the detector plane and is perpendicular to the Primary Axis at the intersection of the beam vector with the detector plane (i.e., it is along the row direction). The Detector Secondary Angle is defined in the plane perpendicular to the Secondary Axis at the point where the central x-ray beam vector intersects the detector plane, with zero degrees in the direction normal to the detector plane. +90 degrees corresponds to the direction toward the top of the image. The Secondary Detector Angle range is -90 to + 90 degrees.

C.8.7.6 XRF Positioner Module

Table C.8-31. XRF Positioner Module Attributes

Attribute Name

Tag

Type

Attribute Description

Distance Source to Detector

(0018,1110)

3

Distance in mm from source to detector center.

Note

This value is traditionally referred to as Source Image Receptor Distance (SID).

Distance Source to Patient

(0018,1111)

3

Distance in mm from source to center of field of view.

Note

This value is traditionally referred to as Source Object Distance (SOD).

Estimated Radiographic Magnification Factor

(0018,1114)

3

Ratio of SID (Source Image Receptor Distance) over SOD (Source Object Distance).

Column Angulation

(0018,1450)

3

Angle of the X-Ray beam in degree relative to an orthogonal axis to the detector plane. Positive values indicate that the tilt is towards the head of the table.

Note

The detector plane is assumed to be parallel to the table plane.


C.8.7.7 X-Ray Tomography Acquisition Module

This Module describes the attributes of a Tomography acquisition (translation of X-Ray source during the acquisition of a single frame image).

Table C.8-32. X-Ray Tomography Acquisition Module Attributes

Attribute Name

Tag

Type

Attribute Description

Tomo Layer Height

(0018,1460)

1

Distance in mm between the table surface and the sharp image plane.

Tomo Angle

(0018,1470)

3

Angle span in degrees of rotation of X-Ray Source during X-Ray acquisition.

Tomo Time

(0018,1480)

3

Time in seconds the source has taken to rotate the Tomo Angle during X-Ray acquisition.

Tomo Type

(0018,1490)

3

Type of tomography.

Defined Terms:

LINEAR

SPIRAL

POLYCYCLOIDAL

CIRCULAR

Tomo Class

(0018,1491)

3

Form of tomography:

Defined Terms:

MOTION

TOMOSYNTHESIS

Number of Tomosynthesis Source Images

(0018,1495)

3

The number of source images used to construct this tomosynthetic image. Only meaningful if Tomo Class (0018,1491) is TOMOSYNTHESIS. These may be listed in Source Image Sequence (0008,2112) of the General Image Module.


C.8.7.8 X-Ray Acquisition Dose Module

This Module describes the attributes related to dose delivery from an X-Ray source during the acquisition of an X-Ray image.

Table C.8-33. X-Ray Acquisition Dose Module Attributes

Attribute Name

Tag

Type

Attribute Description

KVP

(0018,0060)

3

Peak kilo voltage output of the X-Ray generator used.

X-Ray Tube Current

(0018,1151)

3

X-Ray Tube Current in mA.

X-Ray Tube Current in µA

(0018,8151)

3

X-Ray Tube Current in µA.

Exposure Time

(0018,1150)

3

Duration of X-Ray exposure in msec.

Exposure Time in µS

(0018,8150)

3

Duration of X-Ray exposure in µsec.

Exposure

(0018,1152)

3

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current.

Exposure in µAs

(0018,1153)

3

The exposure expressed in µAs, for example calculated from Exposure Time and X-Ray Tube Current.

Distance Source to Detector

(0018,1110)

3

Distance in mm from source to detector center.

Note

This value is traditionally referred to as Source Image Receptor Distance (SID).

Distance Source to Patient

(0018,1111)

3

Distance in mm from source to the table, support or bucky side that is closest to the Imaging Subject, as measured along the central ray of the X-Ray beam.

Note

  1. This definition is less useful in terms of estimating geometric magnification than a measurement to a defined point within the Imaging Subject, but accounts for what is realistically measurable in an automated fashion in a clinical setting.

  2. This measurement does not take into account any air gap between the Imaging Subject and the "front" of the table or bucky.

  3. If the detector is not mounted in a table or bucky, then the actual position relative to the patient is implementation or operator defined.

  4. This value is traditionally referred to as Source Object Distance (SOD).

Image and Fluoroscopy Area Dose Product

(0018,115E)

3

X-Ray dose, measured in dGy*cm*cm, to which the patient was exposed for the acquisition of this image plus any non-digitally recorded fluoroscopy that may have been performed to prepare for the acquisition of this image.

Note

  1. The sum of the area dose product of all images of a Series or a Study may not result in the total area dose product to which the patient was exposed.

  2. This may be an estimated value based on assumptions about the patient's body size and habitus.

Body Part Thickness

(0018,11A0)

3

The average thickness in mm of the body part examined when compressed, if compression has been applied during exposure.

Relative X-Ray Exposure

(0018,1405)

3

Indication of the applied dose, in manufacturer specific units.

Note

  1. This value is intended to provide a single location where manufacturer specific information can be found for annotation on a display or film, that has meaning to a knowledgeable observer.

  2. This may be a calculated or measured value. Examples are the detector entrance dose (KB), the CR sensitivity value (S), or the logarithmic median (lgM).

  3. DICOM specifies standard Attributes in Table 10-23 'Exposure Index Macro', which are recommended.

Entrance Dose

(0040,0302)

3

Average entrance dose value measured in dGy at the surface of the patient­ during the acquisition of this image.

Note

This may be an estimated value based on assumptions about the patient's body size and habitus.

Entrance Dose in mGy

(0040,8302)

3

Average entrance dose value measured in mGy at the surface of the patient­ during the acquisition of this image.

Note

This may be an estimated value based on assumptions about the patient's body size and habitus.

Exposed Area

(0040,0303)

3

Typical dimension of the exposed area at the detector plane. If Rectangular: row dimension followed by column; if Round: diameter. Measured in cm.

Note

  1. The exposed area should be consistent with values specified in the X-Ray Collimator Module, if present.

  2. This may be an estimated value based on assumptions about the patient's body size and habitus.

  3. This attribute is used in the Radiation Dose Module with units in mm (see Section C.4.16, Table C.4-16 “Radiation Dose Module Attributes”).

Distance Source to Entrance

(0040,0306)

3

Distance in mm from the source to the surface of the patient closest to the source during the acquisition of this image.

Note

This may be an estimated value based on assumptions about the patient's body size and habitus.

Comments on Radiation Dose

(0040,0310)

3

User-defined comments on any special conditions related to radiation dose encountered during the acquisition of this image.

X-Ray Output

(0040,0312)

3

The X-Ray output at the patient entrance surface and kVp used to acquire the image, measured in mGy/mAs.

Note

This value may be a calibrated value rather than measured during the exposure.

Half Value Layer

(0040,0314)

3

The thickness of Aluminum in mm required to reduce the X-Ray Output (0040,0312) by a factor of two.

Note

This value may be a calibrated value rather than measured during the exposure.

Organ Dose

(0040,0316)

3

Average organ dose value measured in dGy during the acquisition of this image.

Note

This may be an estimated value.

Organ Exposed

(0040,0318)

3

Organ to which Organ Dose (0040,0316) applies.

Defined Terms:

BREAST

GONADS

BONE MARROW

FETUS

LENS

Note

The anatomic regions described by these terms are those that are particularly radiosensitive and for which it is conventional to obtain organ specific dose parameters.

Anode Target Material

(0018,1191)

3

The primary material in the anode of the X-Ray source.

Defined Terms:

TUNGSTEN

MOLYBDENUM

RHODIUM

Include Table C.8-35a “X-Ray Filtration Macro Attributes”

Rectification Type

(0018,1156)

3

Type of rectification used in the X-Ray generator.

Defined Terms:

SINGLE PHASE

THREE PHASE

CONST POTENTIAL

Include Table 10-23 “Exposure Index Macro Attributes”


C.8.7.9 X-Ray Generation Module

This Module describes the attributes related to generation of X-Rays during the acquisition of an X-Ray image.

Table C.8-34. X-Ray Generation Module Attributes

Attribute Name

Tag

Type

Attribute Description

KVP

(0018,0060)

3

Peak kilo voltage output of the X-Ray generator used.

X-Ray Tube Current

(0018,1151)

3

X-Ray Tube Current in mA.

X-Ray Tube Current in µA

(0018,8151)

3

X-Ray Tube Current in µA.

Exposure Time

(0018,1150)

3

Duration of X-Ray exposure in msec.

Exposure Time in µS

(0018,8150)

3

Duration of X-Ray exposure in µsec.

Exposure

(0018,1152)

3

The exposure expressed in mAs, for example calculated from Exposure Time and X-Ray Tube Current.

Exposure in µAs

(0018,1153)

3

The exposure expressed in µAs, for example calculated from Exposure Time and X-Ray Tube Current.

Exposure Control Mode

(0018,7060)

3

Type of exposure control.

Defined Terms:

MANUAL

AUTOMATIC

Exposure Control Mode Description

(0018,7062)

3

Text description of the mechanism of exposure control.

May describe the number and type of exposure sensors or position of the sensitive area of the imaging detector.

Exposure Status

(0018,7064)

3

Whether the exposure was normally completed or not.

Defined Terms:

NORMAL

ABORTED

Phototimer Setting

(0018,7065)

3

Nominal percentage phototimer setting, where a more positive value indicates greater exposure and a more negative value indicates less exposure.

Focal Spot(s)

(0018,1190)

3

Nominal focal spot size in mm used to acquire this image.

Anode Target Material

(0018,1191)

3

The primary material in the anode of the X-Ray source.

Defined Terms:

TUNGSTEN

MOLYBDENUM

RHODIUM

Rectification Type

(0018,1156)

3

Type of rectification used in the X-Ray generator.

Defined Terms:

SINGLE PHASE

THREE PHASE

CONST POTENTIAL

Generator ID

(0018,1005)

3

Identifier of the generator


C.8.7.10 X-Ray Filtration Module

This Module describes the attributes related to the filtration of X-Rays during the acquisition of an X-Ray image.

Table C.8-35. X-Ray Filtration Module Attributes

Attribute Name

Tag

Type

Attribute Description

Include Table C.8-35a “X-Ray Filtration Macro Attributes”


Table C.8-35a. X-Ray Filtration Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Filter Type

(0018,1160)

3

Type of filter(s) inserted into the X-Ray beam (e.g., wedges).

Defined Terms:

STRIP

WEDGE

BUTTERFLY

MULTIPLE

NONE

Note

Multiple type of filters can be expressed by a combination, e.g., BUTTERFLY+WEDGE.

Filter Material

(0018,7050)

3

The X-Ray absorbing material used in the filter. May be multi-valued.

Defined Terms:

MOLYBDENUM

ALUMINUM

COPPER

RHODIUM

NIOBIUM

EUROPIUM

LEAD

Filter Thickness Minimum

(0018,7052)

3

The minimum thickness in mm of the X-Ray absorbing material used in the filters. May be multi-valued, with values corresponding to the respective values in Filter Material (0018,7050).

Filter Thickness Maximum

(0018,7054)

3

The maximum thickness in mm of the X-Ray absorbing material used in the filters. May be multi-valued, with values corresponding to the respective values in Filter Material (0018,7050).

Filter Beam Path Length Minimum

(0018,7056)

3

The minimum length (in mm) of the X-Ray beam path in the Filter Material that is not blocked by collimation. May be multi-valued, with values corresponding to the respective values in Filter Material (0018,7050).

Filter Beam Path Length Maximum

(0018,7058)

3

The maximum length (in mm) of the X-Ray beam path in the Filter Material that is not blocked by collimation. May be multi-valued, with values corresponding to the respective values in Filter Material (0018,7050).


C.8.7.11 X-Ray Grid Module

This Module describes the attributes related to the use of a grid to reduce scatter of X-Rays during the acquisition of an X-Ray image.

Table C.8-36. X-Ray Grid Module Attributes

Attribute Name

Tag

Type

Attribute Description

Grid

(0018,1166)

3

Identifies the grid. May be multi-valued.

Defined Terms:

FIXED

FOCUSED

RECIPROCATING

PARALLEL

CROSSED

NONE

Include Table C.8-36b “X-Ray Grid Description Macro Attributes”


Table C.8-36b. X-Ray Grid Description Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Grid Absorbing Material

(0018,7040)

3

The X-Ray absorbing material used in the grid.

Grid Spacing Material

(0018,7041)

3

The spacing material used in the grid.

Grid Thickness

(0018,7042)

3

The thickness in mm of the X-Ray absorbing material used in the grid.

Grid Pitch

(0018,7044)

3

The pitch in mm of the X-Ray absorbing material used in the grid.

Grid Aspect Ratio

(0018,7046)

3

Ratio of the vertical spacing and horizontal spacing of the X-Ray absorbing material used in the grid. Specified by a pair of integer values where the first value is the vertical size, and the second value is the horizontal size.

Grid Period

(0018,7048)

3

Period in mSec of reciprocation cycle.

Only meaningful if a value of Grid (0018,1166) is RECIPROCATING.

Grid Focal Distance

(0018,704C)

3

Focal distance in mm of a FOCUSED grid.

Grid ID

(0018,1006)

3

Identifier of the grid


C.8.8 Radiotherapy Modules

This Section describes Radiotherapy-specific modules.

Modules defined here make reference to "IEC" coordinate systems and standards. These standards are defined in IEC Standard 61217, "Radiotherapy Equipment - Coordinates, Movements and Scales" (Reference CEI/IEC 61217: 1996).

Note

IEC document 62C/269/CDV "Amendment to IEC 61217: Radiotherapy Equipment - Coordinates, movements and scales" also defines a patient-based coordinate system, and specifies the relationship between the DICOM Patient Coordinate System (see Section C.7.6.2.1.1) and the IEC PATIENT Coordinate System. Rotating the IEC PATIENT Coordinate System described in IEC 62C/269/CDV (1999) by 90 degrees counter-clockwise (in the negative direction) about the x-axis yields the DICOM Patient Coordinate System, i.e., (XDICOM, YDICOM, ZDICOM) = (XIEC, -ZIEC, YIEC). Refer to the latest IEC documentation for the current definition of the IEC PATIENT Coordinate System.

Many of the dosimetry concepts referred to in this document can be found in ICRU Report 50, Prescribing, Recording, and Reporting Photon Beam Therapy, International Commission on Radiation Units and Measurements, 1993.

C.8.8.1 RT Series Module

There exist significant differences in the manner in which RT objects as compared to diagnostic objects. An RT object can be one of several types, and a series of a given object type may be created over a temporal span of several weeks. The RT Series Module has been created to satisfy the requirements of the standard DICOM Query/Retrieve model while including only those attributes relevant to the identification and selection of radiotherapy objects.

Table C.8-37. RT Series Module Attributes

Attribute Name

Tag

Type

Attribute Description

Modality

(0008,0060)

1

Type of equipment that originally acquired the data.

Enumerated Values:

RTIMAGE

RT Image

RTDOSE

RT Dose

RTSTRUCT

RT Structure Set

RTPLAN

RT Plan

RTRECORD

RT Treatment Record

See Section C.8.8.1.1.

Series Instance UID

(0020,000E)

1

Unique identifier of the series.

Series Number

(0020,0011)

2

A number that identifies this series.

Series Date

(0008,0021)

3

Date the Series started.

Series Time

(0008,0031)

3

Time the Series started.

Series Description

(0008,103E)

3

Description of the series.

Series Description Code Sequence

(0008,103F)

3

A coded description of the Series.

Only a single Item is permitted in this sequence.

>Include Table 8.8-1 “Code Sequence Macro Attributes”

No Baseline CID is defined.

Operators' Name

(0008,1070)

2

Name(s) of the operator(s) supporting the Series.

Referenced Performed Procedure Step Sequence

(0008,1111)

3

Uniquely identifies the Performed Procedure Step SOP Instance to which the Series is related.

One or more items are permitted in this sequence.

>Include Table 10-11 “SOP Instance Reference Macro Attributes”

Request Attributes Sequence

(0040,0275)

3

Sequence that contains attributes from the Imaging Service Request.

One or more Items are permitted in this sequence.

>Include Table 10-9 “Request Attributes Macro Attributes”

No Baseline CID is defined.

Include Table 10-16 “Performed Procedure Step Summary Macro Attributes”

No Baseline CID is defined.


C.8.8.1.1 Modality

The Enumerated Value for Modality (0008,0060) shall determined by the IOD.

Enumerated Values if RT Image IOD:

RTIMAGE

Enumerated Values if RT Dose IOD:

RTDOSE

Enumerated Values if RT Structure Set IOD:

RTSTRUCT

Enumerated Values if RT Plan IOD or RT Ion Plan IOD:

RTPLAN

Note

DICOM specifies that a given series shall contain objects of only one Modality, and shall be created by a single device (described in the General Equipment Module). However, in general there may be many series defined for a given modality/device pair. Note that a radiotherapy series is generally created over an extended time interval (unlike in radiology, where all images in an image series are generally created together).

C.8.8.2 RT Image Module

Table C.8-38 contains attributes that describe RT-specific characteristics of a projection image. The image described by these attributes must be a radiotherapy image acquired or calculated using a conical imaging geometry.

Table C.8-38. RT Image Module Attributes

Attribute Name

Tag

Type

Attribute Description

Samples per Pixel

(0028,0002)

1

Number of samples (planes) in this image. See Section C.8.8.2.6.1 for specialization.

Photometric Interpretation

(0028,0004)

1

Specifies the intended interpretation of the pixel data. See Section C.8.8.2.6.2 for specialization.

Bits Allocated

(0028,0100)

1

Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See Section C.8.8.2.6.3 for specialization.

Bits Stored

(0028,0101)

1

Number of bits stored for each pixel sample. Each sample shall have the same number of bits stored. See Section C.8.8.2.6.4 for specialization.

High Bit

(0028,0102)

1

Most significant bit for each pixel sample. Each sample shall have the same high bit. See Section C.8.8.2.6.5 for specialization.

Pixel Representation

(0028,0103)

1

Data representation of the pixel samples. Each sample shall have the same pixel representation. See Section C.8.8.2.6.6 for specialization.

Pixel Intensity Relationship

(0028,1040)

3

The relationship between the Pixel sample values and the X-Ray beam intensity.

Enumerated Values:

LIN

Linearly proportional to X-Ray beam intensity

LOG

Logarithmically proportional to X-Ray beam intensity

See Section C.8.11.3.1.2 for further explanation.

Pixel Intensity Relationship Sign

(0028,1041)

1C

The sign of the relationship between the Pixel sample values stored in Pixel Data (7FE0,0010) and the X-Ray beam intensity.

Required if Pixel Intensity Relationship (0028,1040) is present.

Enumerated Values:

1

Lower pixel values correspond to less X-Ray beam intensity

-1

Higher pixel values correspond to less X-Ray beam intensity

See Section C.8.11.3.1.2 for further explanation.

RT Image Label

(3002,0002)

1

User-defined label for RT Image.

RT Image Name

(3002,0003)

3

User-defined name for RT Image.

RT Image Description

(3002,0004)

3

User-defined description of RT Image.

Image Type

(0008,0008)

1

Image identification characteristics (see Section C.7.6.1.1.2).

Defined Terms for Value 3:

DRR

digitally reconstructed radiograph

PORTAL

digital portal image or portal film image

SIMULATOR

conventional simulator image

RADIOGRAPH

radiographic image

BLANK

image pixels set to background value

FLUENCE

fluence map

Conversion Type

(0008,0064)

2

Describes the kind of image conversion.

Defined Terms:

DV

Digitized Video

DI

Digital Interface

DF

Digitized Film

WSD

Workstation

Reported Values Origin

(3002,000A)

2C

Describes the origin of the parameter values reported in the image. Required if Value 3 of Image Type (0008,0008) is SIMULATOR or PORTAL.

Enumerated Values:

OPERATOR

manually entered by operator

PLAN

planned parameter values

ACTUAL

electronically recorded

RT Image Plane

(3002,000C)

1

Describes whether or not image plane is normal to beam axis.

Enumerated Values:

NORMAL

image plane normal to beam axis

NON_NORMAL

image plane non-normal to beam axis

X-Ray Image Receptor Translation

(3002,000D)

3

Position in (x,y,z) coordinates of origin of IEC X-RAY IMAGE RECEPTOR System in the IEC GANTRY coordinate system (mm). See Note 2.

X-Ray Image Receptor Angle

(3002,000E)

2

X-Ray Image Receptor Angle i.e., orientation of IEC X-RAY IMAGE RECEPTOR coordinate system with respect to IEC GANTRY coordinate system (degrees). See Section C.8.8.2.2.

RT Image Orientation

(3002,0010)

2C

The direction cosines of the first row and the first column with respect to the IEC X-RAY IMAGE RECEPTOR coordinate system. Required if RT Image Plane (3002,000C) is NON_NORMAL. May be present otherwise.

Image Plane Pixel Spacing

(3002,0011)

2

Physical distance (in mm) between the center of each image pixel, specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing. See Section C.8.8.2.3 and Section 10.7.1.3 for further explanation.

RT Image Position

(3002,0012)

2

The x and y coordinates (in mm) of the upper left hand corner of the image, in the IEC X-RAY IMAGE RECEPTOR coordinate system. This is the center of the first pixel transmitted. See Section C.8.8.2.7.

Radiation Machine Name

(3002,0020)

2

User-defined name identifying radiation machine used in acquiring or computing image (i.e., name of conventional simulator, electron accelerator, X-Ray device, or machine modeled when calculating DRR).

Primary Dosimeter Unit

(300A,00B3)

2

Measurement unit of machine dosimeter.

Enumerated Values:

MU

Monitor Unit

MINUTE

minute

Radiation Machine SAD

(3002,0022)

2

Radiation source to Gantry rotation axis distance of radiation machine used in acquiring or computing image (mm).

Radiation Machine SSD

(3002,0024)

3

Source to patient surface distance (in mm) of radiation machine used in acquiring or computing image.

RT Image SID

(3002,0026)

2

Distance from radiation machine source to image plane (in mm) along radiation beam axis. See Section C.8.8.2.3.

Source to Reference Object Distance

(3002,0028)

3

Source to reference object distance (in mm), as used for magnification calculation of RADIOGRAPH and SIMULATOR images.

Referenced RT Plan Sequence

(300C,0002)

3

Sequence of one Class/Instance pair describing RT Plan associated with image.

Only a single item is permitted in this sequence.

>Include Table 10-11 “SOP Instance Reference Macro Attributes”

Referenced Beam Number

(300C,0006)

3

Uniquely identifies the corresponding N-segment treatment beam specified by Beam Number (300A,00C0) within Beam Sequence in RT Beams Module within the RT Plan referenced in Referenced RT Plan Sequence (300C,0002).

Referenced Fraction Group Number

(300C,0022)

3

Identifier of Fraction Group within RT Plan referenced in Referenced RT Plan Sequence (300C,0002).

Fraction Number

(3002,0029)

3

Fraction Number of fraction during which image was acquired, within Fraction Group referenced by Referenced Fraction Group Number (300C,0022) within RT Plan referenced in Referenced RT Plan Sequence (300C,0002).

Start Cumulative Meterset Weight

(300C,0008)

3

Cumulative Meterset Weight within Beam referenced by Referenced Beam Number (300C,0006) at which image acquisition starts.

End Cumulative Meterset Weight

(300C,0009)

3

Cumulative Meterset Weight within Beam referenced by Referenced Beam Number (300C,0006) at which image acquisition ends.

Exposure Sequence

(3002,0030)

3

Sequence of Exposure parameter sets, corresponding to exposures used in generating the image.

One or more items are permitted in this sequence. See Section C.8.8.2.4.

>Referenced Frame Number

(0008,1160)

1C

Identifies corresponding image frame in multi-frame image. Required if there is more than one item in Exposure Sequence (3002,0030), and image is a multi-frame image.

>KVP

(0018,0060)

2C

Peak kilo voltage output (kV) of X-Ray generator used to acquire image. Required if Value 3 of Image Type (0008,0008) is PORTAL, SIMULATOR or RADIOGRAPH.

>Primary Fluence Mode Sequence

(3002,0050)

3

Sequence defining whether the primary fluence of the treatment beam uses a non-standard fluence-shaping.

Only a single Item is permitted in this sequence.

>>Fluence Mode

(3002,0051)

1

Describes whether the fluence shaping is the standard mode for the beam or an alternate.

Enumerated Values:

STANDARD

Uses standard fluence-shaping

NON_STANDARD

Uses a non-standard fluence-shaping mode

>>Fluence Mode ID

(3002,0052)

1C

Identifier for the specific fluence-shaping mode.

Required if Fluence Mode (3002,0051) has value NON_STANDARD.

>X-Ray Tube Current

(0018,1151)

2C

Imaging device X-Ray Tube Current (mA). Required if Value 3 of Image Type (0008,0008) is SIMULATOR or RADIOGRAPH. May be present otherwise.

>X-Ray Tube Current in mA

(0018,9330)

3

X-Ray Tube Current in mA. An average in the case of fluoroscopy (continuous radiation mode).

>Exposure Time

(0018,1150)

2C

Time of X-Ray exposure (msec). Required if Value 3 of Image Type (0008,0008) is SIMULATOR or RADIOGRAPH. May be present otherwise.

>Exposure Time in ms

(0018,9328)

3

Duration of X-Ray exposure in msec.

>Meterset Exposure

(3002,0032)

2C

Treatment machine Meterset duration over which image has been acquired, specified in Monitor units (MU) or minutes as defined by Primary Dosimeter Unit (300A,00B3). Required if Value 3 of Image Type (0008,0008) is PORTAL.

>Diaphragm Position

(3002,0034)

3

Positions of diaphragm jaw pairs (in mm) in IEC BEAM LIMITING DEVICE coordinate axis in the IEC order X1, X2, Y1, Y2.

>Beam Limiting Device Sequence

(300A,00B6)

3

Sequence of beam limiting device (collimator) jaw or leaf (element) positions for given exposure.

One or more items are permitted in this sequence.

>>RT Beam Limiting Device Type

(300A,00B8)

1

Type of beam limiting device (collimator).

Enumerated Values:

X

symmetric jaw pair in IEC X direction

Y

symmetric jaw pair in IEC Y direction

ASYMX

asymmetric jaw pair in IEC X direction

ASYMY

asymmetric pair in IEC Y direction

MLCX

multileaf (multi-element) jaw pair in IEC X direction

MLCY

multileaf (multi-element) jaw pair in IEC Y direction

>>Source to Beam Limiting Device Distance

(300A,00BA)

3

Radiation source to beam limiting device (collimator) distance (mm).

>>Number of Leaf/Jaw Pairs

(300A,00BC)

1

Number of leaf (element) or jaw pairs (equal to 1 for standard beam limiting device jaws).

>>Leaf Position Boundaries

(300A,00BE)

2C

Boundaries (in mm) of beam limiting device (collimator) leaves (elements) in IEC BEAM LIMITING DEVICE coordinate axis appropriate to RT Beam Limiting Device Type (300A,00B8), i.e., X-axis for MLCY, Y-axis for MLCX. Contains N+1 values, where N is the Number of Leaf/Jaw Pairs (300A,00BC), starting from Leaf (Element) Pair 1. Required if RT Beam Limiting Device Type (300A,00B8) is MLCX or MLCY. May be present otherwise.

>>Leaf/Jaw Positions

(300A,011C)

1

Positions of beam limiting device (collimator) leaf or jaw (element) pairs (in mm) in IEC BEAM LIMITING DEVICE coordinate axis appropriate to RT Beam Limiting Device Type (300A,00B8), e.g., X-axis for MLCX, Y-axis for MLCY). Contains 2N values, where N is the Number of Leaf/Jaw Pairs (300A,00BC), in IEC leaf (element) subscript order 101, 102, … 1N, 201, 202, … 2N.

>Gantry Angle

(300A,011E)

3

Treatment machine gantry angle, i.e., orientation of IEC GANTRY coordinate system with respect to IEC FIXED REFERENCE coordinate system (degrees).

>Gantry Pitch Angle

(300A,014A)

3

Gantry Pitch Angle. i.e., the rotation of the IEC GANTRY coordinate system about the X-axis of the IEC GANTRY coordinate system (degrees). See Section C.8.8.25.6.5.

>Beam Limiting Device Angle

(300A,0120)

3

Treatment machine beam limiting device (collimator) angle, i.e., orientation of IEC BEAM LIMITING DEVICE coordinate system with respect to IEC GANTRY coordinate system (degrees).

>Patient Support Angle

(300A,0122)

3

Patient Support angle, i.e., orientation of IEC PATIENT SUPPORT coordinate system with respect to IEC FIXED REFERENCE coordinate system (degrees).

>Table Top Pitch Angle

(300A,0140)

3

Table Top Pitch Angle, i.e., the rotation of the IEC TABLE TOP coordinate system about the X-axis of the IEC TABLE TOP coordinate system (degrees). See Section C.8.8.25.6.2.

>Table Top Roll Angle

(300A,0144)

3

Table Top Roll Angle, i.e., the rotation of the IEC TABLE TOP coordinate system about the Y-axis of the IEC TABLE TOP coordinate system (degrees). See Section C.8.8.25.6.2.

>Table Top Vertical Position

(300A,0128)

3

Table Top Vertical position in IEC TABLE TOP coordinate system (mm).

>Table Top Longitudinal Position

(300A,0129)

3

Table Top Longitudinal position in IEC TABLE TOP coordinate system (mm).

>Table Top Lateral Position

(300A,012A)

3

Table Top Lateral position in IEC TABLE TOP coordinate system (mm).

>Applicator Sequence

(300A,0107)

3

Sequence of Applicators associated with Beam.

Only a single item is permitted in this sequence.

>>Applicator ID

(300A,0108)

1

User or machine supplied identifier for Applicator.

>>Accessory Code

(300A,00F9)

3

An identifier for the accessory intended to be read by a device such as a bar-code reader.

>>Applicator Type

(300A,0109)

1

Type of Applicator.

Defined Terms:

ELECTRON_SQUARE

square electron applicator

ELECTRON_RECT

rectangular electron applicator

ELECTRON_CIRC

circular electron applicator

ELECTRON_SHORT

short electron applicator

ELECTRON_OPEN

open (dummy) electron applicator

PHOTON_SQUARE

square photon applicator

PHOTON_RECT

rectangular photon applicator

PHOTON_CIRC

circular photon applicator

INTRAOPERATIVE

intraoperative (custom) applicator

STEREOTACTIC

stereotactic applicator (deprecated)

>>Applicator Geometry Sequence

(300A,0431)

3

Describes the applicator aperture geometry.

Only a single Item is permitted in this sequence.

>>>Applicator Aperture Shape

(300A,0432)

1

Aperture shape of the applicator.

Defined Terms:

SYM_SQUARE

A square-shaped aperture symmetrical to the central axis.

SYM_RECTANGLE

A rectangular-shaped aperture symmetrical to the central axis.

SYM_CIRCULAR

A circular-shaped aperture symmetrical to the central axis.

>>>Applicator Opening

(300A,0433)

1C

Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system. In case of square-shaped applicator contains the length of the sides of the square. In case of circular-shaped applicators, contains the diameter of the circular aperture.

Required if Applicator Aperture Shape (300A,0432) is SYM_SQUARE or SYM_CIRCULAR.

>>>Applicator Opening X

(300A,0434)

1C

Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system in X-Direction.

Required if Applicator Aperture Shape (300A,0432) is SYM_RECTANGLE.

>>>Applicator Opening Y

(300A,0435)

1C

Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system in Y-Direction.

Required if Applicator Aperture Shape (300A,0432) is SYM_RECTANGLE.

>> Source to Applicator Mounting Position Distance

(300A,0436)

3

Radiation source to applicator mounting position distance (in mm) for current applicator.

>>Applicator Description

(300A,010A)

3

User-defined description for Applicator.

>General Accessory Sequence

(300A,0420)

3

Sequence of General Accessories associated with the beam producing this image.

One or more items are permitted in this sequence.

>>General Accessory Number

(300A,0424)

1

Identification Number of the General Accessory. The value shall be unique within the sequence.

>>General Accessory ID

(300A,0421)

1

User or machine supplied identifier for General Accessory.

>>General Accessory Description

(300A,0422)

3

User supplied description of General Accessory.

>>General Accessory Type

(300A,0423)

3

Specifies the type of accessory.

Defined Terms:

GRATICULE

Accessory tray with a radio-opaque grid

IMAGE_DETECTOR

Image acquisition device positioned in the beam line

RETICLE

Accessory tray with radio-transparent markers or grid