Do X-Rays really cause cancer?

Did you know? Medical procedures amount to 96% of man-made radiation that humans are exposed to.


Studies show that radiation exposure from imaging tests, like x-rays or CT scans, is never safe. Yet, these tests provide valuable information about your health, and allow your physician to make accurate diagnoses. X-rays and CT scans are necessary tools in medicine... they are also classified as carcinogens.

X-ray medical tests have been around for 120 years, when it was discovered that producing a concentrated beam of electrons through the body onto metal film resulted in an internal image of the body. CT scans were developed in the 1970’s and consist of multiple x-rays and thus significantly higher radiation exposure.

The radiation emitted during these procedures is called ionizing radiation – radiation with so much energy, that during interaction with an atom, removes electrons from the atom’s orbit. The atom becomes charged or ionized. When this occurs within the human body, the cell either dies, repairs itself, or mutates incorrectly and can become cancerous.

Your Normal Medical Exposure and Associated Risk

Numerous studies have validated the positive correlation between radiation exposure and cancer risk. Based on these studies, the FDA estimates that exposure to 10 millisieverts (mSv) from an x-ray or CT scan increases the risk of death from cancer by 1 in 2000 (.05%), a relatively small amount. According to, a “study in England of exposure to radiation from CT scans found that children who received a dose of at least 30 mSv to the bone marrow had 3 times the risk of leukemia compared to those who received a dose of 5 mSv or less. For brain tumors, a dose of 50 mSv or more to the brain was linked to more than 3 times the risk.”

  • The average radiation exposure per x-ray is .28 mSvYou would need approximately 36 x-rays throughout your lifetime to raise your risk of cancer by .05%.

  • The average radiation exposure per CT scan is 6.3 mSvAfter approximately two CT scans, your risk of cancer increases by .05%.

CT scans are far more risky than x-rays, yet they are a noninvasive way to study all parts of the body and assist doctors in diagnosing and treating vascular diseases, cancer, spinal problems, internal injuries, trauma and more. [Note: MRI’s, another common diagnostic tool, do not use ionizing radiation.]

Some Perspective – Airport Scanners

The most common airport scanners – the old-school metal detectors and new-school millimeter scanners (the plastic booth) – do not use ionizing radiation. Backscatter scanners (where you stand between the two boxes) average between 0.00005 to 0.0001 mSv per scan. You would need 1,000 to 2,000 airport (backscatter) scans to get a dose equivalent to a single chest x-ray!

Is there a definitive threshold where x-rays go from safe to dangerous?

Unfortunately, it’s not that easy. There is no scientifically validated number of x-rays or CT scans that you are granted in your lifetime without risk of harm. Each test varies in its levels of emitted radiation, and tissues and organs vary in sensitivity to the radiation exposure. But, here’s a very helpful chart that provides details about common imaging tests and their corresponding effective radiation doses.

The Bottom Line | TL;DR

To optimize your longevity and vitality, we recommend avoiding known carcinogens, including radiation, whenever possible. We encourage you to be informed about your tests, understand how much lifetime medical radiation you’ve been exposed to, and be cautious and inquisitive with young children and radiation exposure. However, remember it takes almost 40 x-rays or two CT scans to increase your risk of cancer by .05%. When requested by a physician as a medical tool, you shouldn’t be scared of medical x-rays or CT scans as a cancer risk.

Take Initiative With Medical Radiation

  • Ask questions. Ask your physician why an imaging test will help them determine your treatment. If your doctor explains why it is needed, do not refuse an x-ray or CT scan. In many situations, the risk of not getting a scan (and thus proper treatment) far outweighs the risk of the radiation exposure.
  • Don’t insist on an x-ray or CT scan. Sometimes physicians will order an x-ray because their patient insists on one. Don’t be this patient. Allow your physician to do their job.
  • If you are pregnant, tell your doctor. Radiation exposure is riskier to an unborn baby than to an adult. If pregnant and in need of an imaging test, clearly understand the risks and ask if there are ways to protect the developing fetus.
  • Ask if a gonad shield can be used. Often there are ways to shield the more sensitive tissues and organs.
  • Stay informed to minimize your cancer risk. We are surrounded by carcinogens. There is no scientific evidence enabling us to pinpoint exactly what will keep us healthy and what will make us ill. However, study after study points to actions we can take daily to maintain harmony in our environment, from lifestyle choices, to diet and stress reduction. Find a credible source of information, and keep learning about the many ways to empower yourself.

[Image courtesy of Tom Page]