Often, because your doctor may want to get an image of some of your organs, he may inject a special liquid before the procedure. This "contrast medium" will enhance the image that is produced. However, the contrast medium probably causes the most concern for patients, says Dr. Robert Zimmerman, the executive vice-chair of radiology at New York-Presbyterian Hospital and Weill Cornell Medical Center. A small percentage of patients are allergic to the substances in the medium, causing severe reactions and potentially serious heart problems. Those with allergies to shellfish or iodine may have to switch to an alternate procedure to avoid this risk.
Since they give doctors a full view of your insides, CAT scans are generally used to diagnose more widespread problems than a single broken bone. They can be used to determine the extent of a head injury, osteoporosis and some forms of cancer, along with other, more complex diseases. CAT scans are also used to look for smaller problems that may be missed by a normal X-ray. This includes infection or inflammation of the sinuses and small tumors that may have spread. Sometimes, especially in the case of a sinus CAT scan, you will need to wear special supports to hold your body in the correct position.
While being overexposed to X-rays can cause health problems, the amount that is used in a CAT scan is not enough to cause any problems. To prevent overexposure for your doctor or technician, however, he or she will likely be in a separate room from the CAT scan machine. Usually, this means he is behind a glass window, controlling the scan as you are sent through.
As always, if you have any reason to suspect that you are pregnant, be sure to inform your doctor. If you are breastfeeding, your doctor may suggest waiting 24 hours after a CAT scan to nurse your baby to ensure that the contrast medium is out of your system.
