An integrated system for radiation therapy that includes a synchrotron ion accelerator beam delivery system, and imaging system on the same compact rotating gantry is disclosed. An ion accelerator, accelerating charged particles, is mounted on an annular gantry that rotates about the patient to be treated. The charged particles may be protons or other heavier ions such as helium or carbon. The beam delivery system, which includes bending, focusing, and scanning magnets and other equipment for accurately delivering the ion beam to the patient, is integrated on the same rotating structure. An imaging system which in one embodiment is, but not limited to, a cone beam CT system. The accelerator and imaging system may be configured in a coplanar or non-coplanar arrangement with the rotation plane of the gantry and with the beam delivery system to allow for optimization of the size or functionality of the system.
