Table 3.
Stereotactic Radiosurgery/Stereotactic Body Radiotherapy Reirradiation Dose and Fractionation Schedules and Spinal Cord/Thecal Sac Safety Constraints With a Low Expected Incidence of Radiation Myelopathy24,26,29
| Recommended treatment dose/ fractionation | 18-24 Gy/1 fx | 24 Gy/2 fx | 27-30 Gy /3 fx | 30 Gy/4 fx | 40 Gy/5 fx | ||
|---|---|---|---|---|---|---|---|
| Prior radiotherapy | 2 Gy BED | None | 12.4-14 Gy spinal cord 16 Gy cauda equina |
17 Gy | 20.3 Gy | 23 Gy | 25.3 Gy |
| 20 Gy/5 fx (30 Gy [2/2]) | 9 Gy | 12.2 Gy | 14.5 Gy | 16.2 Gy | 18 Gy | ||
| 30 Gy/10 fx (37.5 Gy [2/2]) | 9 Gy | 12.2 Gy | 14.5 Gy | 16.2 Gy | 18 Gy | ||
| 37.5 Gy/15 fx (42 Gy [2/2]) | 9 Gy | 12.2 Gy | 14.5 Gy | 16.2 Gy | 18 Gy | ||
| 40 Gy/20 fx (40 Gy [2/2]) | NA | 12.2 Gy | 14.5 Gy | 16.2 Gy | 18 Gy | ||
| 45 Gy/25 fx (43 Gy [2/2]) | NA | 12.2 Gy | 14.5 Gy | 16.2 Gy | 18 Gy | ||
| 50 Gy/25 fx (50 Gy [2/2]) | NA | 11 Gy | 12.5 Gy | 14 Gy | 15.5 Gy |
Abbreviations: BED, biologically effective dose; fx, fraction; NA, not available.
Assumes maximum (0.03-cc) dose to spinal cord planning risk volume or thecal sac.