Computed tomographies (called CT/scans) are tests in which a series of transverse X-rays are taken and recorded on magnetic tape. Computers reconstruct the images based on the levels of radiation absorbed by various tissues. 

These tests are given on various parts of the body, but the most common are the cranium, spine, chest, and the upper and lower abdomen. Others include eye orbits, kidneys, the thoracic, biliary tract and liver, and pancreas. 

PURPOSE: To diagnose abnormalities and to monitor the effects of surgery, radiotherapy, or chemotherapy on tumors. 

PROCEDURE: The patient is placed on a radiographic table and a series of transverse X-rays are taken and recorded on magnetic tape.

NORMAL FINDINGS: Structures are of normal symmetry, density, size, shape, and position. ABNORMAL FINDINGS: Altered density or displaced structures may indicate malformation, abscesses, atrophy, edema, lesions, tumors, aneurysms, cysts, and carcinomas.