Table C.8-122 specifies the attributes of the CT Geometry Functional Group macro.
Table C.8-122CT 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 C.220.127.116.11.1. 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 C.18.104.22.168.1. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.|
In Figure C.8-19 the relationship of the Geometric Attributes within the CT Geometry and CT Reconstruction functional groups is shown. The figure, 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.
[pic] Figure C.8-19: Geometry of CT Acquisition System