MODEL RELEASED. CT scan. Doctor reassures a patient about to be scanned by a CT (computed tomography) scanner. Another doctor looks on and makes notes. The patient will pass through the central hole of the CT scanner behind her head. CT scanning is a diagnostic technique in which X- rays are passed through the body at different angles. A computer then produces a cross-sectional image of the tissue. Also known as CAT (computed axial tomography) scanning, this technique provides more detail than X-rays used by themselves. It also reduces the amount of dangerous radiation to which the patient is exposed.