Docs / OrientationXMedConPatientBased
2. Patient Based
As told for the equipment based coordinate system, the patient based coordinate system is simply a variation on the three slice orientations which are supported by (X)MedCon. We learned from the DICOM 3.0 standard that the axes are as follows:
As we also learned from the equipment based coordinate system, the row and column unit vectors of a slice (image) are defined with the direction cosines. In the patient based coordinate system an extra tag is used to define the direction in the patient of both vectors. The DICOM syntax is:
The abbreviations used in this DICOM tag tell where the unit vector is pointing to:
(X)MedCon supports the following four orthogonal patient orientations:
Note: Here you see that in case of a patient lying supine head first, the coordinate system coincide with the equipment based system.