Radiation levels used with computed axial tomography (CAT scans) are higher than those used in regular x-rays. Although some patients are concerned about radiation exposure from a CAT scan, they should weigh the potential risks of the procedure against the potential life-saving benefits of the information gleaned from the scan.

In rare cases, a contrast solution used in a CAT scan may cause an allergic reaction in the form of mild itching or hives (small, raised reddened areas of skin). In more severe reactions, shortness of breath and swelling of the throat or other body areas may occur. Patients who experience any of these symptoms during the procedure should immediately alert the healthcare professional administering the CAT scan.

Patients should inform their physician of the following: 

• Pregnancy. Another exam will likely be substituted to reduce the risk of exposing the fetus to radiation.
  
  
• Asthma or allergies. Contrast mediums, which are sometimes used to better highlight certain regions of the body, can produce allergic reactions in some people, especially those with a history of asthma or allergies.
  
  
• Other medical conditions. Certain medical conditions also may increase the likelihood of an allergic reaction to contrast mediums. These include:
  
• • Diabetes
  • Heart disease
  • Kidney problems
  • Thyroid conditions