DICOM PS3.3 2023a - Information Object Definitions

C.36.29 RT Patient Position Acquisition Instruction Module

The RT Patient Position Acquisition Instruction Module contains information required by a Patient Position Acquisition System (PPAS) when specifying acquisition of data to detect the patient position before, during or after the delivery specified by an RT Radiation SOP Instance or Treatment Position Group in a RT Radiation Set IOD Instance.

The RT Patient Position Acquisition Instruction Module consists of a sequence of one or more acquisition tasks. Every acquisition task consists of one or more acquisition subtasks (e.g. two subtasks are required in case of a dual plane acquisition task).

Table C.36.29-1. RT Patient Position Acquisition Instruction Module Attributes

Attribute Name

Tag

Type

Description

Include Table 10.32-1 “Entity Long Labeling Macro Attributes”

Acquisition Task Sequence

(3002,0118)

1

The types and details of acquisitions which are requested by the current Instance.

One or more Items shall be included in this Sequence.

>Acquisition Task Index

(3002,011C)

1

Index of this acquisition task in this Sequence.

The value shall start at 1 and increase monotonically by 1.

>Acquisition Task Workitem Code Sequence

(3002,0119)

1

The Workitem code of the acquisition task.

Only a single Item shall be included in this Sequence.

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

DCID 9242 “Radiotherapy Acquisition Workitem Definition”.

>Acquisition Task Applicability Sequence

(3002,0124)

1C

The RT Radiation Set, RT Radiation Instances or the Treatment Position Groups to which the acquisition task is applicable.

Required if RT Radiation Set, RT Radiation Instances or Treatment Position Groups exist whose treatment position is guided by this acquisition task.

Note

In some treatment scenarios, acquisitions may be performed prior to the completion of RT Radiation Instances or Treatment Position Groups.

>>Include Table C.36.2.3.3-1 “RT Patient Position Scope With Legacy Support Macro Attributes”

>RT Acquisition Patient Position Sequence

(3002,0108)

2

The position of the patient when performing this acquisition task.

Only a single Item shall be included in this Sequence.

>>Include Table C.36.2.3.2-1 “RT Patient Position Macro Attributes”

>Acquisition Subtask Sequence

(3002,011A)

1

The types and details of acquisitions which are part of the acquisition task.

One or more Items shall be included in this Sequence.

The number of Items shall be as defined in C.36.29.1.

>>Acquisition Subtask Index

(3002,011D)

1

Index of this acquisition subtask in this Sequence.

The value shall start at 1 and increase monotonically by 1.

>>Subtask Workitem Code Sequence

(3002,011B)

1

The type of acquisition subtask.

Only a single Item shall be included in this Sequence.

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

DCID 9263 “KV Imaging Acquisition Techniques”.

DCID 9264 “MV Imaging Acquisition Techniques”.

>>Acquisition Signal Type

(3002,0129)

1

Type of signal used for acquisition.

Defined Terms:

KV

kilovolt X-Ray

MV

Megavolt X-Ray

>>Acquisition Method

(3002,012A)

1

Method used for acquisition.

Defined Terms:

PROJECTION

Projection radiography

CT

Computed Tomography

>>Position Acquisition Template Identification Sequence

(3002,011F)

3

Identifies an acquisition template containing a set of parameters to be used when acquiring data for patient position detection.

Note

Values of parameters explicitly defined below in this acquisition subtask Item override values specified in the acquisition template identified in this Sequence.

Only a single Item is permitted in this Sequence.

>>>Position Acquisition Template Name

(3002,0121)

1

User defined name of the position acquisition template.

>>>Position Acquisition Template Code Sequence

(3002,0122)

1C

Code identifying the position acquisition template.

Required if Position Acquisition Template ID (3002,0120) not present. May be present otherwise.

Only a single Item shall be included in this Sequence.

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

No Baseline CID defined.

See Section C.36.29.2.1

>>>Position Acquisition Template ID

(3002,0120)

1C

Identifier of the position acquisition template.

Required if Position Acquisition Template Code Sequence (3002,0122) is not present. May be present otherwise.

>>>Position Acquisition Template Description

(3002,0123)

2

User-defined description of the position acquisition template.

>>Referenced Baseline Parameters RT Radiation Instance Sequence

(3002,011E)

1C

RT Radiation SOP or RT Plan Instance that defines baseline parameter values for acquisition, which are modified by parameter values increments in this Subtask.

Required if Imaging Source Location Specification Type (3002,0111) has the value RELATIVE_PARAMS or Imaging Aperture Specification Type (3002,0115) has the value BEAM or RELATIVE_TO_BEAM.

Only a single Item shall be included in this Sequence.

>>>Include Table 10-11 “SOP Instance Reference Macro Attributes”

>>>Referenced Beam Number

(300C,0006)

1C

Uniquely identifies the Beam specified by Beam Number (300A,00C0) in the referenced SOP Instance.

Required, if the referenced SOP Instance has the SOP Class UID RT Plan ("1.2.840.10008.5.1.4.1.1.481.5") or RT Ion Plan ("1.2.840.10008.5.1.4.1.1.481.8").

>>Referenced Device Index

(300A,0607)

1C

The value of Device Index (3010,0039) from the Acquisition Device Sequence (3002,0117) corresponding to the device to be used for acquisition.

Required if Number of Acquisition Devices (3002,0116) is greater than one.

>>RT Device Distance Reference Location Code Sequence

(300A,0659)

1C

Point of reference used for measuring the distance to various devices.

Required if the current Item contains any Attributes which refer to the Base Beam Modifier Coordinate System.

Only a single item shall be included in this Sequence.

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

DCID 9261 “Patient Position Acquisition Radiation Source Locations”.

>>RT Beam Modifier Definition Distance

(300A,0688)

1C

Absolute distance in mm along the z-axis of the Base Beam Modifier Coordinate System from the reference location specified by RT Device Distance Reference Location Code Sequence (300A,0659) to the Beam Modifier Definition Plane.

The value shall be greater than or equal to zero.

Required if RT Device Distance Reference Location Code Sequence (300A,0659) is present.

See Section C.36.1.1.9.

>>Acquisition Initiation Sequence

(3002,0135)

3

Description of how to the acquisition is triggered.

One or more Items are permitted in this Sequence.

>>>Include Table 10-2 “Content Item Macro Attributes”

DTID 15307 “Acquisition Initiation Parameters”.

>>KV Imaging Generation Parameters Sequence

(3002,0127)

1C

Parameters for kV Imaging Acquisitions.

Required if the value of Acquisition Signal Type (3002,0129) is KV.

Only a single Item shall be included in this Sequence.

>>>Include Table C.36.2.4.6-1 “KV Radiation Image Acquisition Parameters Macro Attributes”

>>MV Imaging Generation Parameters Sequence

(3002,0128)

1C

Parameters for MV Imaging Acquisitions.

Required if the value of Acquisition Signal Type (3002,0129) is MV.

Only a single Item shall be included in this Sequence.

>>>Include Table C.36.2.4.7-1 “MV Radiation Image Acquisition Parameters Macro Attributes”

>>Projection Imaging Acquisition Parameter Sequence

(3002,0125)

1C

Parameters for Projection Image Acquisitions.

Required if the value of Acquisition Method (3002,012A) is PROJECTION.

Only a single Item shall be included in this Sequence.

>>>Include Table C.36.2.4.1-1 “RT Projection Imaging Request Geometry Macro Attributes”

>>>Include Table C.36.2.4.4-1 “RT Imaging Aperture Macro Attributes”

>>CT Imaging Acquisition Parameter Sequence

(3002,0126)

1C

Parameters for CT Image Acquisitions.

Required if the value of Acquisition Method (3002,012A) is CT.

Only a single Item shall be included in this Sequence.

>>>Include Table C.36.2.4.5-1 “3D RT Cone-Beam Imaging Geometry Macro Attributes”

>>Device-Specific Acquisition Parameter Sequence

(3002,0131)

3

User-specified device-specific acquisition parameters applicable to the device executing this Acquisition Subtask.

One or more Items are permitted in this Sequence.

>>>Include Table 10-2 “Content Item Macro Attributes”

No Baseline TID defined.

>>Additional RT Accessory Device Sequence

(3002,0130)

1C

Additional devices used during the acquisition of the reference position artifacts.

Required if additional RT Accessory Devices are to be used during patient position acquisition.

One or more Items shall be included in this Sequence.

>>>Referenced Device Index

(300A,0607)

1

Reference to an Item identified by the Device Index (3010,0039) in the General Accessory Definition Sequence (300A,0671).

>>>Device-Specific Acquisition Parameter Sequence

(3002,0131)

3

User-specified device-specific acquisition parameters applicable to the device of the current Item.

One or more Items are permitted in this Sequence.

>>>>Include Table 10-2 “Content Item Macro Attributes”

No Baseline TID defined.

>>Referenced Position Reference Instance Sequence

(3002,0132)

3

SOP Instances which may be used to provide a positional reference for verification of patient position in the current acquisition subtask.

One or more Items are permitted in this Sequence.

>>>Include Table 10.37-1 “Related Information Entities Macro Attributes”

DCID 9267 “Patient Positioning Related Object Purposes”.


C.36.29.1 Patient Position Reference Acquisition Subtask Sequence Multiplicity

For the codes defined in Table C.36.29.1-1 the number of Items in the Acquisition Subtask Sequence (3002,011A) is determined by the code in the Acquisition Task Workitem Code Sequence (3002,0119) as follows:


For codes not in this table, the number of Items is not constrained.

DICOM PS3.3 2023a - Information Object Definitions