Table C.8.22-14 specifies the attributes of the PET Position Functional Group macro.
Table C.8.22-14PET POSITION MACRO ATTRIBUTES
|Attribute Name||Tag||Type||Attribute Description|
|PET Position Sequence||(0018,9735)||1||Contains the attributes defining the PET geometry. Only a single Item shall be included in this sequence.|
|>Table Position||(0018,9327)||1C||Relative longitudinal position of acquisition location of this frame in mm from an implementation specific reference point. Shall be relative to the same reference point for all frames in this SOP Instance, but may be different from the reference point in other SOP Instances. Positions as the table moves into the gantry viewed from the front are more negative. Notes: 1. For contiguous slices reconstructed from multiple detectors one would expect different values for adjacent slices. 2. Lateral positioning or tilting or swiveling are not described. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.|
|>Data Collection Center (Patient)||(0018,9313)||1C||The x, y, and z coordinates (in the patient coordinate system) in mm of the center of the region in which data were collected. See C.22.214.171.124.1. Required if Frame Type (0008,9007) Value 1 equals ORIGINAL. May be present otherwise.|
|>Reconstruction Target Center (Patient)||(0018,9318)||1C||The x, y, and z coordinates (in the patient coordinate system) of the reconstruction center target point as used for reconstruction in mm. See C.126.96.36.199.1. Note: If the reconstructed image is not magnified or panned the value corresponds with the Data Collection Center (0018,9313) attribute. Required if Frame Type (0008,9007) Value 1 equals ORIGINAL. May be present otherwise.|
In Figure C.8.22-1 the relationship of the Geometric Attributes within the PET Geometry and PET 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.
Figure C.8.22-1: Geometry of PET Acquisition System