BeamSite™ is a camera system that enables live visualization of the treatment beam on a patient during radiotherapy. It is an optically based system that is non-patient contacting and produces no radiation. When the treatment beam is on, BeamSite captures images of Cherenkov light emitted from the patient’s skin during radiotherapy to provide an optical map of the treatment beam on the patient. When the treatment beam is off, the system provided continuous background images of the treatment area under ambient light illumination. The BeamSite system consists of a camera, a workstation with preinstalled BeamSite software, and a monitor to be used by clinical radiotherapy teams to a) visually observe the patient and the Cherenkov light emitted from irradiated surface anatomy, and b) review the treatment images, if necessary.