In today’s medical world where defensive medicine is frequently practiced, over a
lifetime, substantial exposure to medical X-rays is common. The FDA estimates
that exposure to 10 mSv from an imaging test would be expected to increase the
risk of death from cancer by about one chance in 2,000. Studies of young women
exposed to high doses of X-rays to the chest and spine have found an increased risk
of breast cancer in later life. Studies comparing people with meningioma (a usually
benign brain tumor) are more likely to have had frequent dental X-rays than those
without the tumors.

A study in England of exposure to radiation from CT (computed tomography X-ray)
scans found that children who received a dose of at least 30 mGy (the same as 30
mSv and about equal to 10 years of background radiation) to the bone marrow had
three times the risk of leukemia compared to those who received a dose of 5 mGy
or less. A dose of 50 mGy or more to the brain was linked to more than three times
the risk of brain tumors. A single CT scan can easily exceed 150 or even 1500 times
a conventional X-ray, and multiple CT scans can deliver a radiation dose equivalent
to many years of background radiation.

According to one calculation, if current overuse continues, it will lead to 3% to 5%
of U.S. cancers. However, some X-ray studies cause minimal exposures, for example,
the approximate radiation dose from a chest X-ray is 0.1 mSv, the equivalent
of 10 days of background radiation. A single dental X-ray is about the same as an
average day’s background radiation, and a bone density scan even less.
For a table of radiation dose comparing background radiation with medical procedures
prepared by the ACR (American College of Radiology) and the RSNA (Radiological
Society of North America),130 go to

The increased risk of cancer from exposure to any single test is likely to be very
small. And it is reassuring that most studies have not documented an increased risk
of cancer after imaging tests that use X-rays. But radiation exposure is cumulative
over a lifetime. So imaging tests that use radiation should only be undertaken when
medically indicated, and the parts of the body that aren’t being imaged should be

Another question that may be raised is the risk of radiation from the treatment of
cancer. According to the American Cancer Society, “When considering radiation
exposure from radiation therapy treatment for cancer, the benefits generally outweigh
the risks. Overall, radiation therapy alone does not appear to be a very strong
cause of second cancers.”

This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel