Table 3.
SBRT Dosimetric Factors | n = 80 patients |
---|---|
Median CTV V80 (range) | 90% (60–99) |
Median PTV V80 (range) | 88% (57–93) |
Median spinal cord Dmax/BED-Dmax (range) | 11.8 Gy (2–18.4)/37.8 Gy2 (2.7–74.7) |
Median spinal cord PRV Dmax/BED-Dmax (range) | 14.3 Gy (2–20)/50.9 Gy2 (2.7–80) |
Median thecal sac Dmax/BED-Dmax (range) | 17 Gy (2.9–30)/70.13 Gy2 (4.9–125.9) |
Abbreviations: PTV, planning target volume; V80, volume (%) receiving 80% of the prescribed dose; BED, biologically effective dose; Gy10, BED calculated with a/b = 10; Gy2, BED calculated with a/b = 2; Dmax, dose to the maximum point volume; thecal sac dose refers to levels below the spinal cord and typically below the 1st lumbar vertebrae.