CT (computer tomography), sometimes called a CAT scan, is a diagnostic procedure in which cross-sectional pictures of the body are made by special x-ray scanner.

To study internal parts of the body, such as the brain or chest, in greater detail than conventional X-rays. CT offers some advantages over other X-ray techniques in diagnosing diseases because it clearly shows the shape and exact location of organs, soft tissues and bones.

A CT scan is used to help identify problems such as cancers, cardiovascular disease, infectious disease, trauma and musculoskeletal disorders. A CT scan may be ordered if you have had a traumatic injury (such as blood clots or skull fractures), infection, tumor or other abnormal structures of the body. At times a CAT scan is ordered in an attempt to explain the cause of certain symptoms that you might be experiencing. For example, a CT scan of the brain might be performed to help find out why you are experiencing headaches and also to check the brain's structure, to find tumors and to detect possible blood clots after a head injury. A scan of the spine can be done to diagnose spinal lesions, tissue damage, or to monitor effects of spinal surgery or therapy.

The procedure is painless. A patient lies very still on a table that passes through a doughnut-shaped X-ray machine. The machine, which is linked to a computer, rotates around the patient, taking pictures of one thin slice of tissue after another. To obtain a clearer picture, the patient may be given a solution of an X-ray dye to drink or get an injection into the arm vein before the CT is done.

The length of the procedure can take from 10 to 30 minutes, depending on the size of the area to be scanned.

Yes. A CT scan is a low-risk, noninvasive procedure. CT does involve exposure to radiation, which is slightly higher than from a regular X-ray. However, the benefit of an accurate diagnosis usually outweighs the risk associated with radiation exposure. The typical radiation dose from a CT exam is equivalent to the amount of natural background radiation received over a year's time.

Some patients may have an adverse reaction to the contrast dye that may be used. To make sure it is safe for you, a radiologist or technologist will check your medical history to see if you have had any allergies to shellfish, iodine or certain dyes, and whether you have a history of diabetes, asthma, a heart condition, kidney problems or thyroid conditions. These conditions may indicate a higher risk of reaction to the contrast dye. The risk of serious allergic reaction to contrast dye-containing iodine is rare, and radiology departments are well equipped to deal with them.

If you believe that you may be pregnant, inform the radiologist before undergoing any CT scan.

If a contrast dye will be used during the scan, you'll be asked to refrain from eating for 4 hours before the scan. During the scan, you'll be asked to remove all metal objects, jewelry and any removable dental work, depending on the part of the body that is being scanned.

Call 503.435.6380, Monday through Friday between the hours of 7:30 am and 5:00 pm.

Check in at the radiology desk on the main floor of the hospital. For directions to the hospital, click here.

A board certified radiologist will carefully review your scan. A transcribed report will be forwarded to your healthcare provider within two working days. Your healthcare provider will discuss the results with you.