C.8.15.3.6 CT Geometry Macro

C.8.15.3.6 CT Geometry Macro
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Table C.8-122 specifies the attributes of the CT Geometry Functional Group Macro.

Table C.8-122. CT Geometry Macro Attributes

Attribute Name	Tag	Type	Attribute Description
CT Geometry Sequence	(0018,9312)	1	Contains the attributes defining the CT geometry. Only a single Item shall be included in this Sequence.
>Distance Source to Detector	(0018,1110)	1C	Distance in mm from source to detector center. See Section C.8.15.3.6.1. Note This value is traditionally referred to as Source Image Receptor Distance (SID). Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Distance Source to Data Collection Center	(0018,9335)	1C	Distance in mm from source to data collection center. See Section C.8.15.3.6.1. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

Attribute Name

Tag

Type

Attribute Description

CT Geometry Sequence

(0018,9312)

Contains the attributes defining the CT geometry.

Only a single Item shall be included in this Sequence.

>Distance Source to Detector

(0018,1110)

Distance in mm from source to detector center. See Section C.8.15.3.6.1.

Note

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

Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

>Distance Source to Data Collection Center

(0018,9335)

Distance in mm from source to data collection center. See Section C.8.15.3.6.1.

Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

C.8.15.3.6.1 Relationships Between CT Geometric Attributes (Informative)

In Figure C.8-19 the relationship of the Geometric Attributes within the CT Geometry and CT Reconstruction functional groups is shown. Figure C.8-19, viewed from the front of the gantry (where the table enters the gantry), is informative only and is not meant to represent a standardization of an equipment-based frame of reference.

Figure C.8-19. Geometry of CT Acquisition System

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