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4 facts and myths about imaging and radiation. Learn the facts

Reviewed 8/31/2023

4 facts and myths about imaging and radiation

Imaging tests are used to look inside the body. They help doctors diagnose conditions and determine the best treatments. There are various types of imaging tests, many of which use radiation. The type of imaging recommended for you will depend on the goal of the test, your condition and the part of your body being examined.

To help you understand more about imaging and radiation, here are some common myths and facts.

Myth or fact: You should avoid all radiation.

MYTH. We’re exposed to radiation every day. We get it from the air, outer space, the ground and even the food we eat. Scientists measure radiation in millisieverts (mSv). It’s estimated that the average person in the U.S. receives a dose of about 3 mSv per year just through natural means.

For comparison, the radiation you receive from an x-ray of your ankle is 0.001 mSv. That’s equal to 3 hours of natural radiation. A CT scan of your lungs imparts 1.5 mSv, or the equivalent of six months of natural radiation. Even that amount is considered a very low health risk.

If you need imaging that uses radiation, the radiologist will ensure you’re exposed to the lowest amount possible for an effective test.

Myth or fact: All imaging tests use some form of radiation.

MYTH. Plain x-rays, CT scans and nuclear scans use radiation. But ultrasound and magnetic resonance imaging (MRI) scans don’t.

An ultrasound uses sound waves to create an image. MRIs use a large magnet and radio waves.

Myth or fact: Imaging tests that use radiation are considered safe.

FACT. Many activities we think of as safe—like taking a walk—carry some degree of risk. Similarly, imaging tests that use radiation are considered safe. Radiologists use the lowest radiation possible to get effective images. It would take ultra-high levels of radiation—far more than those used in diagnostic imaging—to potentially cause cancer later in life.

Still, you want to minimize your exposure to radiation when possible. If you’re worried that your imaging test will expose you to unnecessary radiation, discuss your concerns with your doctor or the radiologist. Maybe you’ve had a similar test done recently that could provide the information they need. Or you may have the option of a different test that wouldn’t expose you to radiation.

Myth or fact: Radiation tests can make you infertile.

MYTH. Very high radiation doses can harm eggs or sperm. But the amount of radiation used in diagnostic radiology is very low. No studies have shown that low-level radiation exposure to eggs or sperm causes birth defects or miscarriage. Even cancer patients whose ovaries received fairly high levels of radiation have shown no negative lasting effects.

You can lower your risk from an imaging test by letting your doctor know if you are—or think you could be—pregnant before having the procedure. Your doctor might want to postpone or modify it to lower the amount of radiation you’ll receive.

Learn more about specific imaging tests and how they might be used.

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