Radiotoxicity in robotic radiosurgery: proposing a new quality index for optimizing the treatment planning of brain metastases.

V12 is a main parameter for assessing plan quality in terms of radiotoxicity. The index f12 defined as the ratio of V12 from the actual plan with the evaluated V12 from our model describes the conformity of an optimally possible V12 and thus can be used as a new quality index for optimizing treatment plans.