Abstract: A system is equipped with a computer-controlled rotating gantry and includes at least one radiation source mounted to the gantry. The radiation source moves along an arcuate path as the gantry rotates and emits an x-ray beam at a first energy level for imaging of a small animal and emits an x-ray beam at a second energy level for radiation therapy of the small animal. The first energy level is less than the second energy level. The system's imaging capabilities are implemented with the use of a flat panel detector.