From: Optimal organ-sparing intensity-modulated radiation therapy (IMRT) regimen for the treatment of locally advanced anal canal carcinoma: a comparison of conventional and IMRT plans
Organ
Threshold dose (Gy)
Volume above limit (%)
Bladder
30
80
40
0
50
Small Bowel
Genitalia/perineum
35–45
5–10
48
Iliac crests
10
20
25–30
Femoral heads
45
5
55