Radiation therapy apparatus for treating tumor disease, has positioning device which is more extensible to front end when beam head in secondary mode of operation is seen by positioning device before front surface

摘要

The apparatus (11) has a beam head (21) for generating therapeutic radiation directed on the patients (17). The beam head is arranged within the gantry (13) in such a manner that front surface (25) of gantry in primary mode of operation arranges the positioning device (19) to front end of therapy apparatus, when the beam head in the primary mode of operation is seen by the positioning device behind the front surface. The positioning device is more extensible to the front end when beam head in secondary mode of operation is seen by positioning device before front surface.