ASMR 2016

At the start of treatment

• Single CT introduces systematic errors*:  Delineation errors  Organ position and shape at time of localization  Phantom transfer errors o Geometric imaging error o Treatment planning system error o Linear accelerator geometry error o Set-up error at time of localization  TPS beam algorithm error  Breathing positional error

*McKenzie et al., BIR 2003 Image courtesy: Marcel van Herk