ABSTRACT
Current modern radiotherapy approaches, like intensitymodulated radiation therapy (IMRT) or even therapy employing proton and heavy ion beams, aim to widen the therapeutic window by enhancing the dose conformity to prede£ned threedimensional (3D) tumor geometries. Designing steep dose
gradients between radiation targets and organs at risk compromises one of the major tasks of modern treatment planning, where an “ideal” dose delivery on an “ideal and static” patient geometry is assumed. However, prior to the advent of imageguided radiation therapy (IGRT), it was di›cult to assess the quantitative accuracy between these planned ideal dose patterns and the ones that were actually delivered to the speci£c patient.
