What Is It?

Computed tomography, also called CT or CT scan, is a process that uses X-rays and computer technology to make cross-sectional images of the body. A series of X-ray pictures, each a thin slice, are put together in a computer to form a three-dimensional view of the inside of your body. If an X-ray is like looking at a photo of a heart, a CT scan is like looking at a model that you can pick up and examine from any angle.

In a CT scan, X-rays pass through the body and are analyzed by a computer. The computer builds an image based on the amount of X-rays passing through tissues of different thickness. For example, bone appears white on a CT scan, and gas bubbles in the stomach and intestines appear black.

You can have a CT scan in an outpatient facility or in a hospital. The procedure is painless and takes about 20 minutes, but can be longer or shorter depending on the area of the body being scanned.