IMRT

Dose-volume constraints for IMRT: small bowel  Baglan et al. (n=40, 3D-CRT)  V15 < 150cc: no grade 3+ acute GI toxicity  V15 > 150cc: 50% grade 3+ acute GI toxicity  Gunnlaugsson et al. (n=28, 3D-CRT)  V15 ≤ 150cc: 11% diarrhea  V15 > 150cc: 52% diarrhea  Tho et al. (n=41, 3D-CRT)  V5-V30 correlated with severity of diarrhea  Yang et al. (n=177, IMRT/3D-CRT)  V45 < 3%: no grade 2+ diarrhea  V45 ≥ 27%: 20% grade 2+ diarrhea  Reis et al. (n=45, 3D-CRT)  V5 < 292cc: 29% grade 2-3 diarrhea  V5 > 292cc: 82% grade 2-3 diarrhea  QUANTEC (Marks LB et al.): V15 < 120cc (< 10% risk of severe acute GI toxicity)

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