For specific domains , such as Radiotherapy , an older format , the DICOM RT Structure Set , which can encode 3D patient relative coordinate isocontours ( only ) is used .
Some format workstations produce these as well instead of SRs .
For specific domains , such as Radiotherapy , an older format , the DICOM RT Structure Set , which can encode 3D patient relative coordinate isocontours ( only ) is used , and some non-RT workstations produce these as well instead of SRs .