1. A system for treating a target within a body of a patient, said system comprising: a radiating apparatus irradiating a treatment volume having a known position; a patient support supporting the patient such that the target to be treated is located adjacent to the treatment volume; a scanner scanning the body and creating body images of the body to monitor the position of the target; and a controller responsive to the monitored position of the target for selectively activating the radiating apparatus to irradiate the target when the target is at least partially coincident with the treatment volume.