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. 2013 Oct;15(10):1413–1419. doi: 10.1093/neuonc/not101

Table 3.

SBRT dosimetric factors

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.