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CTV to PTV margins with respect to IGRT
practice: a survey of RO in the US
Treatment site
First few fractions
weekly
daily
Head and Neck
5 mm
4.9 mm
4.8 mm
Lung
6.4
6.6
6.2
Prostate IMRT
4.9
4.5
4.6
Nabavizadeh et al IJROBP 2015
(showing only data for CBCT)
Survey shows that margins are more dependent on the physician
than on imaging type/frequency