From: Whole brain radiotherapy with adjuvant or concomitant boost in brain metastasis: dosimetric comparison between helical and volumetric IMRT technique
Organ at risk
Dose constraints
SIB
SRS
Brain (without PTV)
Dmean ≤ 32 Gy
V35 Gy < 15 %
V40 Gy < 5 %
V45 Gy < 0 %
V12Gy < 10 cc
Brainstem
Dmax < 35Gy
Excluded
Chiasm
Optic nerve
Lens
Dmax < 5 Gy