A method and apparatus for delivering therapeutic radiation (112) to a radiotherapy target (119) in a patient (114) includes a diagnostic X-ray source (124, 125) connected to a treatment couch (116), facing a first side of the patient. An imaging device (118) is connected to the treatment couch facing a second side of the patient. The diagnostic X-ray source and the imaging device move in lockstep with movement of the treatment couch. The patient is in a fixed position relative to the treatment couch.