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What about second cancer risk?
VMAT and multibeam-IMRT vs. 3D-CRT and forward-IMRT:
•
More beams
larger volume of normal tissue is exposed to a
‘low-dose-bath’
•
Require a longer beam-on time
integral dose can increase because of head leakage and
collimator scatter
•
Second cancer risk can increase
however, absolute risk on second cancer risk is low
Abo Madyan RO 2014, Ibrahim BMC Cancer 2012, Boyce NEJM 2002