DICOM PS3.3 2018d - Information Object Definitions

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.

Entrance Dose Derivation

(0040,8303)

3

Describes what type of dose is represented by the values of Entrance Dose (0040,0302) and Entrance Dose in mGy (0040,8302).

Enumerated Values:

IAK

Represents air kerma at the entrance surface, no backscatter included, no air kerma to tissue dose conversion applied.

ESAK

Represents air kerma at the entrance surface, with backscatter included, no air kerma to tissue dose conversion applied.

ESDBS

Represents absorbed dose in tissue at the entrance surface, with backscatter included.

ESDNOBS

Represents absorbed dose in tissue at the entrance surface, without backscatter included.

Only meaningful if Entrance Dose (0040,0302) or Entrance Dose in mGy (0040,8302) is present.

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 was previously used in the Radiation Dose Module with units in mm. This use has been retired. See PS3.3 2017c.

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”


DICOM PS3.3 2018d - Information Object Definitions