A CT scan is a medical procedure that uses x-rays and computer technology to create detailed images of the inside of your body. CT stands for computed tomography. During a CT scan, you lie on a table and an x-ray machine circles around you, taking pictures of cross-sections of your body. The pictures are sent to a computer, where they are converted into 3-D images. Your doctor can use these images to diagnose problems or plan treatments. CT scans are painless and take about 30 minutes. You may be given a contrast material or get an intravenous (IV) line before the CT scan starts. The contrast material helps the radiologist see certain areas more clearly. If you have an IV line, the contrast material will be injected through it during the CT scan. After the CT scan is complete, you can go home and resume your normal activities. You should not have any side effects from the contrast material used during a CT scan. However, if you have an allergy to iodine, tell your doctor before having a CT scan so that he or she can prescribe medicine to lessen the chance of an allergic reaction. Very few might feel some discomfort from lying on the table during the procedure. You may also hear buzzing and clicking noises as the x-ray machine moves around you during the CT scan. Most people find these noises faint and do not find them bothersome. Some people may feel anxious or claustrophobic while lying still inside the small space of a CT scanner for long periods of time.