A radiation therapy and scanning system is provided. The radiation and therapy scanning system includes a therapy source adapted to deliver a predetermined dose of treatment radiation along an axis to a patient positioned in a scan field, a stationary scanning source producing an electron beam, and a detector positioned to partially circumscribe the scan field. The radiation therapy and scanning system also includes a target arranged concentric with the detector and located opposite the detector across the scan field, the target positioned at an angle θ to the axis such that when the electron beam impinges on the target the target transmits radiation through the scan field to the detector.