MODEL RELEASED. CT scanning. Radiographer preparing a patient about to undergo a CT scan. Computed tomography (CT) is a diagnostic technique that sends small doses of X-rays through the body at different angles to produce cross-sectional images of the area scanned. The patient, and the bed on which she is lying, is passed through the scanner. A computer compiles the X-ray data into multiple image slices. CT scans are widely used to locate tumours, as they are good at distinguishing soft tissue from bone.