Almost everyone is exposed to radiation from some form of imaging test every year. This may be through dental X-rays, a mammogram, a CT scan or an X-ray for a broken bone.
Most people know that high-dose radiation exposure can increase the risk for cancer, and some people worry that imaging tests can also raise their risk. In general, the radiation dose used in medical imaging is low, so there’s no need to worry.
If you want to understand the link better, however, UVA radiologist Mike Hanley, MD has developed a calculator to help you determine your radiation exposure and cancer risk.
The Cancer-Radiation Connection
According to the American Cancer Society, X-rays and gamma rays can cause cancer. The study of this connection was initiated and is sustained by tragedies such as the bombing of Nagasaki and Hiroshima, as well as the Chernobyl nuclear accident. Because high doses are so strongly linked to cancer, it makes sense that people might assume that low doses must have some effect — however, no conclusive research currently links contemporary medical imaging technology with cancer. It is possible that earlier technology exposed people to more radiation than today’s machines, but imaging technology continues to advance rapidly. Scientists continually strive to ensure that CT scans and X-rays emit the smallest doses of radiation possible.
“We don’t definitively know the effect of low doses of radiation from X-rays and CT scans,” Dr. Hanley says. “To be safe, we assume there’s a small risk and do everything we can to minimize that risk.”
Understanding Your Risk
Using Dr. Hanley’s calculator, you can select the type of scan you’re having done, then enter your age and gender. The site calculates your estimated radiation exposure and increased cancer risk. The calculator also provides a baseline risk of developing cancer, which is based on the American Cancer Society‘s estimated lifetime risk numbers.
Dr. Hanley says the main purpose of the calculator is to help patients weigh the risks against the benefits of any imaging test.
“If a test can find cancer early and has a small, if not negligible, risk, then it’s worth having,” Dr. Hanley advises. “The calculator is meant to give an estimate of cancer risk so patients can have an informed conversation with their doctor.”
The website also features a range of educational materials that can help you evaluate imaging scans and decide whether you prefer to talk to your doctor about alternatives. Ultrasounds and MRIs don’t use radiation, for example, and they may be appropriate options.
“When performed correctly and for appropriate reasons, CT scans and X-rays are safe and save lives,” Dr. Hanley contends.
UVA Cancer Center offers screenings that are administered with radiation exposure best practices.Learn More