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How many fields?
- depends on the complexity of the case
- size of the PTV, size of the patient
‘Standard’ 3D-CRT bladder treatment : 33 x 2.0 Gy:
- 3 field (18MV) 3D CRT: CTV bladder + 15mm = PTV
4-5 field technique reduces
high dose areas…..
but increases low dose areas
do not be afraid of adding
beams
85-90%