Patent ID: 8299447

Claim:
A rotating irradiation apparatus comprising: an irradiation device that irradiates a charged particle beam; a frame on which the irradiation device is mounted and which rotates the irradiation device so that a patient lying on a treatment table fixed to a stationary floor surface is irradiated with the charged particle beam; a ring that is rotatably held on an inner periphery of the frame; an opening/closing-type floor which is provided inside the ring and of which a portion through which the irradiation device passes is openable and closable; and a drive motor that reversely rotates the ring in synchronization with the rotation of the irradiation device, and is controlled by feedback so as to maintain the horizontal opening/closing-type floor, wherein the opening/closing-type floor is formed of a plurality of segmented slide floors, wherein portions of the opening/closing-type floor are slidable relative to other portions of the opening/closing-type floor and the opening/closing-type floor forms an access floor only in the frame without being connected to the stationary floor surface when being closed.