A computerised tomography scan (CT scan) is a special type of x-ray that gives a highly detailed picture of the organs and other structures in your body.
CT scans are used for a range of diagnostic and monitoring purposes. They are usually done at a hospital or a radiology service. It usually takes about 30-40 minutes to complete this painless test. You will be asked to lie flat on a table, while it moves through the CT scanner, which is large and round like a doughnut.
A dye may be injected into a vein, probably in your arm, before the scan. This will make the pictures that the scanner takes clearer. You will be asked not to eat or drink for a while before you have your scan. Most people are able to go home as soon as their scan is over.
CT scan patient information The Royal Australian and New Zealand College of Radiologists