CT Scan

About the Procedure

A CT Scan (Computed Tomography), sometimes known as a CAT Scan (Computed Axial Tomography), is a method of viewing sections of the body in two-dimensions through the use of X-ray technology. The procedure is performed while a patient lays in a tube-shaped machine which takes pictures in cross-sectional slices. The images can be examined on a computer monitor, printed or transferred to a CD. Some procedures use a contrast agent administered intravenously using iodine or barium. The dye may also be swallowed or introduced with an enema. CT scans are used in preventive medicine, for diagnosing and measuring cancerous tumors, detecting vascular diseases and skeletal injuries, for emergency treatment, and for guidance during surgical procedures. It is preferred over traditional X-rays because the images have greater clarity and detail.

This thirty minute (or less) procedure is performed in the radiology area of a hospital or out-patient facility. Patients lay on their back or side on a flat table. If a contrast agent is to be used, it is set-up at this time. The table slides through a large tube-like machine which is narrow and slightly higher than the patient's head. As the table moves back and forth through the machine there are pinging and whirring noises. At certain points, the technologist may ask patients to hold their breath or remain very still because CT scan pictures can blur with movement. There is no pain associated with the procedure but patients with chronic pain or phobias may find laying in the machine difficult and should ask for assistance from the technologist.

What to Know Before the Procedure

A CT scan is completely non-invasive and, other than lying inside the scanning machine, nothing touches the patient. The amount of radiation passed through the body varies depending on the type of scan. There are no immediate side effects from the X-rays but the radiation accumulates over the patient's lifetime. An increased risk of cancer has been identified as a result of long-term accumulation of radiation. Technologists are trained to use the lowest level of radiation to obtain the desired results.

Some people are allergic to the contrast material, particularly iodine, and there is potential for a life-threatening reaction. Patients who are aware of an existing allergy to dye need to tell the technologist who may be able to use an alternative material or administer medication to reduce the severity of a reaction. The dye may also contribute to kidney damage especially in patients whose kidney function is already at risk. Pregnancy is contraindicated for CT scans because it exposes the fetus to radiation. The mother should seek the advice of her obstetrician and a radiologist. Recent studies show little risk from contrast material for nursing babies and no longer recommend waiting 24 hours to breastfeed following the procedure.

Little preparation is required for a CT scan except to wear comfortable clothes. Patients are requested to complete paperwork regarding their health history, current medical conditions, medications and allergies, particularly to contrast materials (dyes) if they are to be used during the procedure. Women who are pregnant or suspect they are need to inform the technologist. Breastfeeding mothers who choose not to wait 24 hours before feeding their milk to their baby can prepare ahead by pumping milk to be used at this time.

What to Know After the Procedure

Once the CT scan is completed, the patient may leave the facility and resume all normal activities. If a contrast agent has been used, special instructions will be given. Results are interpreted by a radiologist who will send a report to the referring physician. Further treatment, if necessary, will be discussed with the doctor.

If you Need to Travel Outside of your Local Hospital

A CT scan is an in-and-out procedure with no side effects and no restrictions afterwards. It would not be sensible to travel long distances for such a common procedure. However, if you are traveling to a location across the country or to another country for another procedure, then you may also require a CT scan at that point.