DICOM PS3.3 2021e - Information Object Definitions

C.34.17 Performed XA Acquisition Module

This Module contains acquisition parameter values for a performed XA imaging procedure. The purpose of this Module is to record all relevant parameters, not just to record the values that were constrained in the executed Defined Protocol (if any).

This Module contains Attributes that are "set" on the machine, e.g., to affect its behavior, but not those that describe the results. The latter may be found in the acquired images.

Note

The acquisition parameters for an XA imaging system are those involved in the creation of the 2D ORIGINAL pixel data. They include two different activities: the control of the X-Ray generation and beam formation to obtain the output signal from the X-Ray detector (so-called raw data), and the linear and image-independent corrections of the raw data.

The XA Defined Acquisition Protocol is typically selected manually from the device console, although rules may exist on the device to pre-select a default protocol based on procedure type and patient characteristics. Each Protocol Element contains the parameters of one acquisition mode. For a biplane system, the parameters for both planes are contained in the same protocol element. The operator may choose which Protocol Elements are performed during the procedure.

Table C.34.17-1. Performed XA Acquisition Module Attributes

Attribute Name

Tag

Type

Attribute Description

Acquisition Protocol Element Sequence

(0018,9920)

2

Parameter values for each Protocol Element in the acquisition protocol. Each item in the sequence describes one Element. Elements are performed in the order of their Protocol Element Number (0018,9921).

See Section C.34.9.1.

Zero or more Items shall be included in this Sequence.

>Include Table 10.28-1 “Protocol Element Identification Macro Attributes”

>Include Table 10.41-1 “General Procedure Protocol Reference Macro Attributes”

>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)

>Acquisition Mode

(0018,11B0)

1

Manufacturer-defined name of the acquisition mode described by this Protocol Element.

>Scan Options

(0018,0022)

3

Identifies the acquisition technique of this Protocol Element.

Defined Terms:

TOMO

Tomography

CHASE

Bolus Chasing

STEP

Stepping

ROTA

Rotation

>Dose Mode Name

(0018,11B1)

3

Manufacturer-defined name of the dose level program (e.g. High, Medium, Low).

>Acquired Subtraction Mask Flag

(0018,11B2)

3

Identifies that the device acquired mask images for subtraction.

Enumerated Values:

YES

NO

>Fluoroscopy Persistence Flag

(0018,11B3)

3

Identifies that the device has persistently kept a block of continuously acquired fluoroscopy data. Applicable if the equipment supports local storage of fluoroscopy data.

Enumerated Values:

YES

NO

See Section C.34.17.1.

>Fluoroscopy Last Image Hold Persistence Flag

(0018,11B4)

3

Identifies that the device has persistently kept the last image of the acquired fluoroscopy data. Applicable if the equipment supports local storage of Fluoro Last Image Hold data.

Enumerated Values:

YES

NO

See Section C.34.17.1.

>Upper Limit Number Of Persistent Fluoroscopy Frames

(0018,11B5)

3

Upper limit of the number of fluoroscopy frames to be persistently kept.

> Contrast/Bolus Auto Injection Trigger Flag

(0018,11B6)

3

Identifies that the contrast/bolus injection was automatically controlled.

Enumerated Values:

YES

NO

>Contrast/Bolus Injection Delay

(0018,11B7)

3

Time delay in seconds of the injection of contrast/bolus with respect to the X-Ray start. Negative values mean that injection starts before X-Ray start.

>Contrast/Bolus Ingredient Opaque

(0018,9425)

3

Whether the absorption of the contrast/bolus ingredient was greater than the absorption of water (tissue).

Enumerated Values:

YES

NO

>XA Acquisition Phase Details Sequence

(0018,11B8)

3

Parameter values for each of the phases. Each item in the sequence describes one phase.

One or more Items are permitted in this sequence.

See Section C.34.17.2.

>>XA Acquisition Duration

(0018,11BD)

3

The time in seconds used for the acquisition of this phase.

>>XA Acquisition Frame Rate

(0018,11B9)

1

The frame rate in frames per second used for this phase.

>Planes in Acquisition

(0018,9410)

3

The multiplicity of planes that could be used simultaneously during the acquisition.

See Section C.8.19.2.1.3.

>XA Plane Details Sequence

(0018,11BA)

3

Parameter values for each of the planes (or X-Ray beams) operating simultaneously in the Acquisition Protocol Element. Each item in the sequence describes one plane.

One or more Items are permitted in this Sequence.

Note

A Biplane system is recommended to create two items, one for each plane, even if the parameters of both planes are the same.

>>Plane Identification

(0018,9457)

1

Identification of the plane to which the parameters of this sequence item applies.

Defined Terms:

MONOPLANE

PLANE A

PLANE B

>>Beam Number

(300A,00C0)

1

Identification number of the beam.

The value shall be 1 if Plane Identification (0018,9457) equals MONOPLANE or PLANE A, and shall be 2 if Plane Identification (0018,9457) equals PLANE B.

>>KVP

(0018,0060)

3

Peak kilo voltage output of the x-ray generator.

>>X-Ray Tube Current in mA

(0018,9330)

3

Nominal X-ray tube current in milliamperes.

>>Exposure Time in ms

(0018,9328)

3

Duration of exposure for this Acquisition Protocol Element in milliseconds.

>>Exposure in mAs

(0018,9332)

3

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

>>Average Pulse Width

(0018,1154)

3

Average width of X-Ray pulse in msec.

>>Focal Spot(s)

(0018,1190)

3

Used nominal size of the focal spot in mm. The Attribute may only have one or two values, for devices with variable focal spot, small dimension followed by large dimension.

>>Acquisition Field Of View Label

(0018,11BB)

3

Manufacturer-defined name of the Field of View label displayed on the acquisition console. Each label corresponds to a FOV dimension applied during the acquisition.

>>Field of View Dimension(s) in Float

(0018,9461)

3

Dimensions in mm of the Field of View, that is the image pixels stored in Pixel Data (7FE0,0010). If Field of View Shape (0018,1147) is:

RECTANGLE: row dimension followed by column.

ROUND: diameter.

HEXAGONAL: diameter of the circle circumscribing the hexagon.

>>X-Ray Filter Details Sequence

(0018,11BC)

3

Parameter values for each of the filters inserted simultaneously into the X-Ray beam. Each item in the sequence describes one filter.

One or more Items shall be included in this sequence.

>>>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 Type

(0018,1160)

3

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

Defined Terms:

STRIP

WEDGE

BUTTERFLY

MULTIPLE

FLAT

NONE

>>>Filter Material

(0018,7050)

3

The X-Ray absorbing material used in the filter.

Defined Terms:

MOLYBDENUM

ALUMINUM

COPPER

RHODIUM

NIOBIUM

EUROPIUM

LEAD

>>Detector Binning

(0018,701A)

3

Number of active detectors used to generate a single pixel. Specified as number of row detectors per pixel then column.

>>Bits Stored

(0028,0101)

3

Number of bits stored for each pixel sample in the acquired images.

>>Rows

(0028,0010)

3

Number of rows in the acquired images.

>>Columns

(0028,0011)

3

Number of columns in the acquired images.

>>Primary Positioner Scan Start Angle

(0018,9510)

3

Start position of the primary positioner in degrees.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>>Secondary Positioner Scan Start Angle

(0018,9511)

3

Start position of the secondary positioner in degrees.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>>Primary Positioner Scan Arc

(0018,9508)

3

Total amount of rotation of the primary positioner in degrees.

Applicable only to protocol elements for rotational acquisitions, i.e. Scan Options (0018,0022) equals ROTA.

>>Secondary Positioner Scan Arc

(0018,9509)

3

Total amount of rotation of the secondary positioner in degrees.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>>Rotational Primary Angle Rotation Step

(0018,9514)

3

Constant increment of the primary positioner angle in degrees. Positive increment indicates an increasing value of the primary positioner angle.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>>Rotational Secondary Angle Rotation Step

(0018,9515)

3

Constant increment of the secondary positioner angle in degrees. Positive increment indicates an increasing value of the secondary positioner angle.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>>Rotational SID (distance source to detector)

(0018,1110)

3

Distance from source to receptor plane perpendicular to the receptor plane in mm.

Applicable only to protocol elements for rotational acquisitions, i.e., Scan Options (0018,0022) equals ROTA.

>Requested Series Description

(0018,9937)

3

Text that is intended to be copied into the Series Description (0008,103E) of the images resulting from this Acquisition Protocol Element.

>Requested Series Description Code Sequence

(0018,11C1)

3

A code that is intended to be copied into the Series Description Code Sequence (0008,103F) of the images resulting from this Acquisition Protocol Element.

Only a single Item is permitted in this Sequence

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

No Baseline CID is defined.

>Content Qualification

(0018,9004)

3

Content Qualification Indicator of instances resulting from this Acquisition Protocol Element.

Enumerated Values:

PRODUCT

RESEARCH

SERVICE

See Section C.34.18.2.


C.34.17.1 Fluoroscopy Persistence

An XA device acquires fluoroscopy to be primarily displayed in real time during image-guided procedures.

Fluoroscopy Persistence means that the fluoroscopy pixel data is not discarded immetiately after the acquisition, but rather it is kept locally on the acquisition device for further use, either to be reviewed, processed, stored on media and/or transmitted as DICOM instances to another DICOM device.

The Attributes Fluoroscopy Persistence Flag (0018,11B3) and Fluoroscopy Last Image Hold Persistence Flag (0018,11B4) do not suggest or assume any further use of the data other than the local storage on the acquisition device. The workflows related to the presentation, processing or transmission of Fluoroscopy data is handled outside the Acquisition Protocols.

DICOM PS3.3 2021e - Information Object Definitions