Radiation therapy device has second collimator controllable for selective beam setting and removably positioned between first collimator controllable for selective beam setting and treatment surface

摘要

The radiation therapy device has a radiation source (52) positioned to direct a beam along a beam path (12) to a treatment surface (18), a treatment head (24) containing a first collimator controllable for selective beam setting and a second collimator removably positioned between the first collimator and the treatment surface and controllable for selective beam setting. Independent claims are also included for the following: (a) a radiation therapy system (b) an electron collimator (c) and radiation therapy method.