Initially, the CAT scan was used to generate images of only the head, but now it is used for the rest of the body.
To begin imaging, the patient is placed in a tube like scanner. An X-ray source then revolves around the patients body, taking pictures. The computer then puts all the pictures together to produce a clear image.
Previously, X-rays were used to take pictures of bones and other hard parts of the body. X-rays also are used in the CAT scans. But advances in computer technology allow the information collected to be manipulated to create a three-dementional image for a particular body part. Consequently, CAT scans are no longer limited to imaging the bony masses in the body.
The scanner is so sensitive that it can differentiate between muscle and the other surrounding tissues. A CAT scan is so sensitive it can find growths such as tumors that are only 1 millimeter to 2 millimeters.