Megavoltage computed tomography during radiotherapy

摘要

Reduced dose megavoltage CT images are obtained using low flux data resulting from leakage through modulating shutters and/or collected by other means and augmented by incomplete high flux data collected during radiation therapy. The ability to construct tomographic projection sets from significantly varying flux rate data is provided by the use of air scans windowed to account for variations in mechanical leaf movement. These methods are also provide a means of imaging the patient entirely during radiation therapy treatments without any additional scan time.