Self-shielded image guided radiation oncology system

Abstract

An image-guided radiotherapy system adapted to be juxtaposed adjacent a CT scanner comprises a frame having an orifice adapted to permit passage therethrough of a couch on which a patient is positioned, together with a gantry assembly rotatably mounted on the frame in which the gantry assembly comprises a shielding cylinder having an orifice therethrough in alignment with the orifice in the frame. The shielding cylinder has affixed thereto a linac-based treatment head configured to provide radiotherapy, and a beamstop positioned angularly opposite the treatment head to absorb radiation from the treatment head. The shielding cylinder provides sufficient shielding of radiation scattered from the patient and the remainder of the system to not require a conventional vault. In some embodiments an arch may be used instead of a cylinder.

We claim: 
     
         1 . An image-guided radiotherapy system comprising
 a frame having an orifice adapted to permit passage therethrough of a couch on which a patient is positioned,   a gantry assembly rotatably mounted on the frame, the gantry assembly comprising a shielding cylinder having an orifice therethrough in alignment with the orifice in the frame, and   the shielding cylinder having affixed thereto a linac-based treatment head configured to provide radiotherapy, and a beamstop positioned angularly opposite the treatment head to absorb radiation from the treatment head.   
     
     
         2 . An image-guided radiotherapy system comprising
 a shielding arch configured to block x-ray radiation, and   a gantry rotatably mounted to a frame, the gantry having thereon a linac-based treatment head and a beamstop diametrically opposed thereto, with a tunnel passing through both the gantry and the frame configured to receive a couch bearing a patient when the radiotherapy system is juxtaposed adjacent a CT scanner with the tunnel in alignment with a tunnel in the CT scanner.