Published: May 16, 2007
Updated: Aug. 22, 2011
A computed tomography (CT) scan is an x-ray test that takes a series of detailed pictures of the organs inside your body. Each picture is of an area, or 'slice' of the body, similar to the slices of a loaf of bread.
CT scanning is used when your doctor needs more detailed information than can be provided by a physical examination or regular x-rays. One of the main roles is to reveal tumors, particularly those which are small. It is also good for detecting complications of surgery, causes of chest or abdominal pain and extent of internal injury following trauma.
CT scans can be done so that the radiologist can view your internal anatomy in three dimensions (3D). Surgeons sometimes find this type of 3D information useful in planning a surgery.
CT scanning can be done either in Duke University Hospital or Duke Clinic radiology departments. Be sure you know where you are scheduled for the test.
For many types of CT scans, an IV line will be started in your arm by a nurse so that you can receive intravenous contrast material previously referred to as "X-ray dye." If you have had lymph nodes removed under your arm, please tell the nurse so your IV can be started on the opposite side.
You will then be asked to lie flat on a table, which slowly moves you in and out of the scanner. The hole through which you will slide is quite large on present day scanners; therefore, claustrophobia is rarely a problem.
If you are having a CT of the chest or abdomen, you will be asked to hold your breath for up to 30 seconds. The technologist can help you with longer breath holds by giving you some supplemental oxygen or some special breathing maneuvers. If IV contrast is used, it will be given as scanning is started. You may experience a sensation of warmth in your chest and abdomen and perhaps a metallic taste in your mouth during the contrast administration. These symptoms are normal and will subside. If you experience any other symptoms such as nausea, itching, sneezing, shortness of breath or chest discomfort, please alert the nurse immediately. Furthermore, if you feel any pain at the injection site in your arm, alert the nurse immediately.
Expect to be in the Radiology - CT department for one to two hours. Overall, the entire CT scan should require less than five minutes to complete and you should be on the table less than 15 minutes.
In general, there are no special measures to be taken after the procedure. If you received oral or IV contrast, drink plenty of liquids (64 ounces/8 cups) over the rest of the day to flush the contrast out of your body.
While it is not absolutely necessary to have someone with you when you are scanned as an outpatient, it may be helpful. If you develop an adverse reaction that requires treatment, you may receive diphenhydramine (Benadryl®) which causes drowsiness, and could prevent you from driving yourself home.
CT scanning does use x-rays and it would be considered unhealthy if you were exposed in this fashion on a frequent basis (every few days). X-ray exposure is an important consideration particularly in children, young adults and pregnant females (especially in the first three to four months of pregnancy). It is important to note that the amount of radiation received during one or even several CT scans is not considered harmful.
There is a small risk that you may have an allergic reaction to the intravenous contrast material. Rarely, patients are allergic to the oral contrast material. If you have had a reaction to the contrast material from a prior examination (e.g., angiogram, CT scan, or IVP) please alert the nurse or the technologist immediately. Furthermore, please inform the nurse of all your allergies.
Call your doctor immediately if you experience
This article is intended as a resource for patients receiving their cancer care at Duke University Hospital or Duke Clinic. It is not intended to substitute for medical advice from your health care team. If your doctor’s instructions differ from the information in this article, please talk with your doctor before making any changes.