What Are the Risks of a CT Scan?

A computerized tomography (CT) scan can be used to accurately identify health problems inside the body, but it often comes with some risks. One of the main risks of a CT scan is the onset of cancer resulting from the radiation that is distributed during the procedure. An additional concern is an allergic reaction to the dye that frequently is used during a CT scan. Some people are considered particularly susceptible to the risks of a CT scan, including pregnant women, nursing mothers and children. In general, patients usually are advised to obtain a scan only when it is worth it, such as to correctly diagnose a condition that could be life-threatening.

One of the most well-known risks of a CT scan is the amount of radiation to which patients are exposed during a single session. It typically is higher than the amount in a standard X-ray and is considered to be much higher than the level of radiation to which people are exposed via the sun. The result could be an increased risk of cancer, because some studies show that repeated exposure to radiation can lead to this potentially deadly disease. While one or two CT scans are unlikely to increase the risk of cancer by much, undergoing this procedure several times may be risky, which is why most patients are advised to obtain one only when the benefits appear to outweigh the risks. It may even be advisable to obtain a second opinion from a different medical professional when a doctor recommends a CT scan, because some doctors may use this tool more often than necessary.

Another one of the risks of a CT scan involves the dye that often is inserted into the veins before the procedure to get the most accurate results possible. Some people are allergic to this dye and are not aware of this until they break out in hives, get itchy skin or become nauseous. Some find that it either becomes hard to breathe or they begin breathing faster than usual, both of which can be life-threatening. Though it can be hard to predict how a patient will react to the dye during a first CT scan, conditions such as asthma, heart disease and diabetes often increase the chances of a bad reaction. Patients should realize, though, that such risks of a CT scan are rather rare, and usually can be treated immediately to prevent long-term consequences.

There are other types of patients who should be particularly careful about having CT scans, because they also may be especially sensitive to the risks. One example is pregnant women, because the procedure could harm unborn babies as a result of their small size. The same rule applies to children, whose bodies may be more susceptible to the risks of a CT scan, because they generally are smaller than most adults. Nursing mothers usually can undergo a CT scan somewhat safely but are advised to avoid breastfeeding for at least a full day afterward. It should be noted that when a doctor believes there is a life-threatening issue that cannot be diagnosed and treated without a CT scan, children and pregnant women often are encouraged to get the procedure, because the benefits are believed to outweigh the risks.