IMRT

PHENOMENOLOGICAL MODELS

• all models predict an increase in NTCP when increasing the dose and the irradiated volume • they describe the dose-NTCP relationship through a sigmoidal curve • the dose-volume relationship differs for each organ considered; it may also differ for different endpoints within the same organ Parametrization: Position

dose required to obtain a certain level of response (50%: D 50 ) Steepness normalized dose response gradient increase in response for a 1% increase in dose at D 50 level