X-rays, CT scans and other imaging tests have revolutionized the practice of medicine. Without picking up a scalpel, doctors can peer inside the body and locate, diagnose and treat various medical conditions.
But despite their many potential benefits, some of these tests expose patients to small amounts of radiation. And exposure to too much radiation could potentially increase a person's risk for cancer.
While worries about radiation shouldn't keep you from getting a test you need, it is a good idea to take steps to minimize your exposure, according to the U.S. Food and Drug Administration (FDA).
Basis for concern
X-rays and other radiation-based tests use high-energy waves that penetrate the body to create images on film or computer screens. They help doctors see broken bones, tumors or clogged arteries.
The waves also ionize cells, potentially causing them to mutate and perhaps lead to cancer.
All humans are exposed to background ionizing radiation every day, according to the American Cancer Society (ACS). This radiation is found in the cosmic rays of our solar system and in radioactive elements in the soil.
Add medical radiation, and exposure to radiation goes up. The more radiation exposure people have, the higher their risk of cancer, according to the ACS.
Radiation and its medical uses
Medical tests that use radiation include:
X-rays (also called radiography), which are two-dimensional views of the body. They may be used to find broken bones or detect pneumonia, or used in the dental office to view teeth and jaws.
Mammograms, or x-rays of the breast. Mammograms screen for and help diagnose breast cancer.
Computed tomography (CT) scans, which generate 2D images as "slices" that can be stacked to create a 3D view of the body. Uses include detecting or confirming tumors, guiding biopsies, and seeing inside organs.
CT scans are the single largest contributor to medical radiation. They account for about 49% of medical radiation exposure in the U.S. population, according to the National Cancer Institute.
Ultrasounds and magnetic resonance imaging (MRI) tests don't produce radiation.
In addition to being used in tests, radiation is also used—in high, targeted doses—to treat certain kinds of cancer. The radiation kills the cancer cells but can damage other cells too. That can lead to other cancers later in life.
What you can do
There's no doubt that imaging tests have saved or improved millions of lives. Almost always, the benefit of having one outweighs any risks.
But the FDA recommends that consumers take these precautions to keep their exposure as low as possible:
- Don't insist on an x-ray or other radiation-based test if your doctor says there's no need for one—but don't refuse one if your doctor orders it, either.
- Tell the imaging technician in advance if you are, or could be, pregnant.
- Ask if you can use a shield or a protective lead apron to cover areas of the body not being examined in the test.
- When children need a CT scan, make sure the radiology team will use pediatric settings, which use lower doses of radiation.
- Ask your dentist about using lower-dose (E or F) film for x-rays.
- Avoid full-body CT scans touted as ways to screen for disease—they expose you to unnecessary radiation without clear medical benefit.
The FDA also recommends keeping a record of all the imaging tests you and your family receive, including dental x-rays.
Reviewed 7/31/2023