C.36.2.4.2 Matrix-based RT Imaging Geometry Macro

C.36.2.4.2 Matrix-based RT Imaging Geometry Macro (Current)
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The Matrix-based RT Imaging Geometry Macro describes the location of the imaging source and image receptor by the means of matrices with respect to the Equipment Frame of Reference.

Table C.36.2.4.2-1. Matrix-based RT Imaging Geometry Macro Attributes

Attribute Name	Tag	Type	Attribute Description
Imaging Source Position Sequence	(3002,010D)	1	The position of the imaging source. Only a single Item shall be included in this Sequence.
>Referenced Defined Device Index	(300A,0602)	1C	The value of Device Index (3010,0039) from the Acquisition Device Sequence (3002,0117) corresponding to the Acquisition Device used in this Item. Required if Value 1 of Image Type (0008,0008) has the value ORIGINAL or the current Instance was derived from an Instance whereReferenced Defined Device Index (300A,0602) was present in the Imaging Source Position Sequence (3002,010D). May be present otherwise.
>Device Position to Equipment Mapping Matrix	(3002,010F)	1	A rigid, homogeneous 4x4 transformation matrix that maps the Imaging Source Coordinate System to the Equipment Coordinate System. Matrix elements shall be listed in row-major order. See Section C.36.1.1.11.
>Device Position Parameter Sequence	(3002,0110)	2	Device-specific parameters, derived from the Device Position to Equipment Mapping Matrix (3002,010F). See Section C.36.2.4.2.1.1. Zero or more Items shall be included in this sequence.
>>Include Table 10-2 “Content Item Macro Attributes”			DTID 15308 “Imaging Source Geometry Parameters”
Image Receptor Position Sequence	(3002,010E)	1	The position of the image receptor. Only a single Item shall be included in this Sequence.
>Referenced Defined Device Index	(300A,0602)	1C	The value of Device Index (3010,0039) from the Acquisition Device Sequence (3002,0117) corresponding to the Acquisition Device used in this Item. Required if Value 1 of Image Type (0008,0008) has the value ORIGINAL or the current Instance was derived from an Instance where Referenced Defined Device Index (300A,0602) was present in the Image Receptor Position Sequence (3002,010E). May be present otherwise.
>Device Position to Equipment Mapping Matrix	(3002,010F)	1	A rigid, homogeneous 4x4 transformation matrix that maps the Image Receptor Coordinate System to the Equipment Coordinate System. Matrix elements shall be listed in row-major order. See Section C.36.1.1.12.
>Device Position Parameter Sequence	(3002,0110)	2	Device-specific parameters, derived from the Device Position to Equipment Mapping Matrix (3002,010F). See Section C.36.2.4.2.1.1. Zero or more Items shall be included in this sequence.
>>Include Table 10-2 “Content Item Macro Attributes”			DTID 15309 “Image Receptor Geometry Parameters”

C.36.2.4.2.1 Matrix-based RT Imaging Geometry Macro Attribute Descriptions

C.36.2.4.2.1.1 Imaging Source Position Parameter Sequence and Image Receptor Position Parameter Sequence

The Device Position to Equipment Mapping Matrix (3002,010F) is the exclusive source of information to define the location of the imaging source and the image receptor. Imaging devices will solely derive the displacement by this matrix.

Some applications, which do not act as imaging devices and cannot de-compose these matrices into device-specific parameters, may want to informatively display device-specific parameters to the user. The purpose of the Device Position Parameter Sequence (3002,0110) is to facilitate such display. These Sequences are not a substitute for the Device Position to Equipment Mapping Matrix (3002,010F).