Medical Testing Using Radiation and Cancer Risk

Radiology tests and procedures can expose a person to radiation. The amount of radiation depends on the test and what is being imaged. Some tests, such as MRI (magnetic resonance imaging) and ultrasound, use no radiation at all. Over time, exposure to this radiation can increase the risk of cancer.

While there have not been studies following people over time to assess for cancer risk, there are plenty of studies on the amount of radiation received in various tests and a model (called BEIR VII) that calculates how that may result in increased cancer risk.

So, how many tests are too many? The amount of radiation from one scan can vary from machine to machine, even within one institution, depending on the radiologists' protocol. Whether repeat pictures are taken of an area for clarity can also impact how much radiation is received. Different scans have different levels of radiation. For example, a CT scan exposes you to much less radiation than an angiogram of the arteries in your heart.

You should talk to your provider when a scan is ordered. Is this test necessary? What will we learn from it and will this change our treatment plan? Weigh the risks and benefits and make an informed decision about each test.

Learn more about radiology testing and cancer risk from the American College of Radiology, Food & Drug Administration and the American Cancer Society.