Table 4 Target and organs-at-risk definition
| Â | UHW | UPMC | UofT | UVAMC | RSMC |
|---|---|---|---|---|---|
Imaging modality, which is used for GTV definition | MRI and CT | MRI and CT, FDG-PET if available | MRI and CT | CT and MRI | CT, MRI and FDG-PET |
Use of an anatomical target volume concept | Anatomical two dose-level target volume concept | Anatomical target volume concept | Anatomical target volume concept | Anatomical target volume concept | Anatomical target volume concept |
GTV to PTV safety margin | 3 mm | 2 mm; 3 mm in the sacrum. | 2 mm | 2 mm | None |
Protocol if PTV overlaps with the. spinal cord | Two dose-level approach; The OAR spinal cord is always in the PTV-elective and is always excluded from the higher dose PTV-macroscopic | PTV within 1 mm to the spinal cord is excluded from the PTV | PTV is limited by the cord or thecal sac for cauda equina | If this occurs, we either operate to resect part of the tumor or fractionate the radiation. | GTV drawn to edge of OAR |
Treatment of the vertebra superior and inferior to the metastatic vertebra | No | No | No | No | No |
Imaging modality for definition of the spinal cord | Spinal cord in MRI | Spinal cord in MRI | Spinal cord in MRI | Spinal cord in MRI | Spinal canal in CT |
Delineation of the spinal cord in cranio-caudal direction | At least 1 level above and below PTV | 1 level above and below PTV | At least 1 level above and below PTV | 1 level above and below PTV | 1 level above and below PTV |
Safety margins around the spinal cord in axial directions | 1 mm | 1 mm | 1.5 mm | No | 2 mm anterior and 1 mm lateral |
Delineation of the cauda equina | Thecal sac | Thecal sac | Thecal sac | Thecal sac | Thecal sac |
Delineation other OARs (e.g. kidney) | No application of safety margins | No application of safety margins | No application of safety margins | No application of safety margins | No application of safety margins |