The Risks of CAT Scans

Computed axial tomography, or CAT, scans are a test commonly used for diagnosis of internal maladies. CAT scans are noninvasive and show the internal structures of the body in measured slices. A CAT scan is a quick and much less painful alternative to the exploratory surgeries used prior to the availability of this technology.

Cancer

• Excessive use of CAT scanning in diagnosis and monitoring is believed to increase the risk of cancer in patients. While experts have no idea what the lifetime risk of CAT scans is, a study performed at the Columbia University Medical Center says that CAT scans could account for as much as two percent of the total cancers in the United States over the next 20 to 30 years.

Radiation Dosage

• All x-ray procedures expose patients to various doses of radiation; however, a CAT scan of the abdomen can be 50 times the dose of radiation as an x-ray of the same area. This dose of radiation is about the same amount that a person might receive from background sources such as the sun over a period of five years. Furthermore, a CAT scan of the chest is equivalent to having 10 to 20 mammograms. It is not fully documented how this amount of radiation administered regularly will affect humans.

During Pregnancy

• Don't be surprised if you are asked to submit to a pregnancy test prior to having a CAT scan. CAT scans are a low-risk procedure but can expose an unborn baby to radiation. This risk is often presented as being worth the benefit of an accurate diagnosis, but prolonged exposure can cause birth defects.

Nursing Mothers

• Regular CAT scans have no adverse effect on nursing mothers, but some CAT scans require a dye called contrast to be injected or taken orally. Contrast causes the internal organs to be opaque in the CAT scan results. Nursing mothers must wait at least 24 hours before resuming breast-feeding after undergoing a CAT scan that involves contrast.

Allergy

• While it is rare, there is some risk of allergic reaction to the contrast used for certain CAT scans. The contrast contains iodine, and allergy to this substance can cause reactions that range from itching and hives to nausea and rapid breathing. Allergic reactions that escalate to difficulty breathing are rare.

Children

• There are some important things to consider when deciding on whether to perform a CAT scan on a child. A child should not have a CAT scan unless it is absolutely necessary for diagnosis. Furthermore, children should not be subjected to additional scans unless it just cannot be avoided. CAT scanners are calibrated for adults, and that means a child will receive six times the amount of radiation needed to produce a clear picture.