Computed Tomography is sometimes called a CAT or CT scan.
The scanner uses X-rays to take a series of very detailed pictures of sections of the body. The X-rays pass through the body and are detected by sensors on the other side of the machine. This information then goes to a computer that produces a picture of the structures of the inside of your body.
These tests are commonly used to assist doctors and help identify abnormalities in the chest, abdomen, bones and blood vessels. Your images are created by a radiographer and the pictures are reported/diagnosed by a special doctor who is trained to interpret them (radiologist).
This scan is then used by the doctor to plan your individual treatment, using the information from the CT scan, making it as accurate as possible.
Please see Radiology for more information