CT Scans

A computed tomography, CT scan is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs.


CT scans show images of the body with great detail. It can also be a good alternative for patients with pacemaker or other implanted metal devices, who are not good candidates for MRI.

How to Prepare

How you prepare for a CT scan depends on which part of your body is being scanned. Some CT scans require you to ingest a contrast medium before the scan. A contrast medium or agent refers to a substance taken by mouth, enema or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen more clearly. Contrast examinations may require you to fast for a certain period of time before the procedure. Your physician will notify you of this prior to the procedure.

Depending on the part of your body being scanned, your doctor may ask you to take laxatives, enemas or suppositories, or temporarily modify your diet.

The Procedure

During the CT scan you lie on a table that slides through the opening of a large device called the gantry. The table can be raised, lowered or tilted. Straps and pillows may help you stay in position. As the X-ray tube rotates around your body, the table slowly moves through the gantry. While the table is moving you may need to hold your breath to avoid blurring the images.

During this time, a technologist in a shielded room supervises the CT scan and monitors the images as they appear on the computer screen. The technologist can see and hear you, and you can communicate via intercom.

Expect the exam to last no more than a few minutes depending on the preparation needed and whether it includes the use of contrast medium. It will be necessary for you to remain still and quiet during the procedure.

After the Procedure

After the exam you can return to your normal routine. If you were given a contrast medium, your doctor or the radiology staff may give you special instructions, such as drinking fluids to help remove the medium from your body.

Possible Risks

Although rare, the contrast medium involved in a CT scan poses a slight risk of allergic reaction. Most reactions result in hives or itchiness. In very rare instances, an allergic reaction might cause swelling in your throat or other areas of your body. If you experience any symptoms during or after your CT exam, immediately tell your technologist or doctor.

CT scan risks are similar to those of conventional X-rays. During the CT scan, you are briefly exposed to radiation. But doctors and other scientists believe that CT scans provide enough valuable information to outweigh the associated risks. Be sure to inform your doctor if:

  • You are pregnant. If you are pregnant, your doctor may recommend another type of exam to reduce the possible risk of exposing your fetus to radiation.
  • You have asthma or allergies. If you have asthma or allergies and your CT scan requires a contrast medium, there is a slight risk of an allergic reaction to the contrast medium.
  • You have certain medical conditions. Diabetes, asthma, heart disease, kidney problems or thyroid conditions also increase your risk of a reaction to contrast medium.
  • A blood test to measure kidney function may be required prior to the exam. Your healthcare provider will notify you if this is necessary.

You will need to let your physician know if you have ever had a reaction to any contrast dye, or if you are allergic to iodine or seafood. If you are pregnant or think you may be pregnant, you should notify your physician. If you are claustrophobic or tend to become anxious easily, tell your physician ahead of time, as he/she may prescribe a mild sedative for you before the procedure to make you more comfortable. 

For more information about CT Scans at Wilson Health, please call (937) 498-5336.