Patent ID: 8750453

Claim:
A therapy delivery system using a proton beam, in which a proton beam for treatment is delivered to an irradiation target, said therapy system comprising: a rotatable gantry having a gantry rotation axis; a beam generator for generating said proton beam; a patient positioner configured to position a patient within the rotatable gantry and generally along the gantry rotation axis; a therapy delivery unit interconnected to the rotatable gantry, allowing the gantry to rotate about the gantry rotation axis as the gantry rotates, the therapy delivery unit capable of receiving a proton beam and directing it along a therapy delivery path, thereby delivering a radiation therapy dose to a patient on the patient positioner; an x-ray source configured to generate x-rays and mounted to said rotatable gantry, said x-ray source configured to: deliver x-rays along an x-ray source axis; revolve about the gantry rotation axis; and emit x-rays at a plurality of rotation angles of said rotatable gantry; and one or more x-ray imagers also mounted to said rotatable gantry, wherein the imagers are retractable toward the gantry and away from the gantry rotation axis, wherein the system prevents collisions between the imagers and other system components during rotation or other movement of the gantry by retracting the imagers toward the gantry, and wherein the imagers are configured to: detect the x-rays from the x-ray source; revolve about the gantry rotation axis; and use the detected x-rays to produce images of the patient.