Ionizing radiation and cancer
Near ultraviolet light and ultraviolet A (UV-A), both have about the same wavelengths.
They, and visible light, infrared, microwave, radio waves, and low-frequency
radio radiation are all examples of non-ionizing radiation. In contrast,
far-ultraviolet light and UV-B, X-rays, gamma rays, and all particle radiation from
radioactive decay are regarded as ionizing. Ionizing radiation carries enough energy
to liberate electrons from atoms, thereby ionizing them. Ions can damage the
DNA inside of cells and cause mutations that result in cancer, so exposure to all
types of ionizing radiation increases cancer risk.
The sources of ionizing radiation can be natural, for example, from radon gas, or
human-made from a nuclear accident or medical procedures such as routine X-rays
and computed tomography X-ray (CT) scans. Atomic bomb survivors were found
to have an increased risk of developing cancer at multiple sites in the body. The
level of risk for cancer increases as the dose of radiation received increases. Since
cancers from radiation may take years to develop, cancers may occur many years
after exposure.
In the U.S., several federal agencies require employers to limit, monitor, and disclose
radiation exposures. Depending on the workplace, the Occupational Safety
and Health Administration (OSHA), the Nuclear Regulatory Commission, and the
Department of Energy, set the safety standards for workplace radiation exposure.
For the majority of people, exposure to natural sources of radiation makes up most
of the annual dose of ionizing radiation. The two major sources of this natural
radiation are cosmic rays and radionuclides originating from the earth’s crust. Radionuclides
are pervasive in the ground, rocks, building materials, and drinking water.
About half of the annual dose of ionizing radiation from natural sources comes
from the inhalation of the radon gas that arises from the decay of radium-226. It
is estimated that the average person receives a dose of about 3 mSv per year of
background radiation from naturally occurring radioactive materials and cosmic
radiation from outer space. These natural “background” doses vary throughout the
country and are greater for people living at high altitudes.
Although there is probably no threshold below which ionizing radiation can be considered
completely safe, most studies have not detected an increased risk of cancer
among people exposed to low levels of radiation. Even so, scientists and regulatory
agencies agree that even small doses of gamma and x-radiation probably increase
cancer risk, although by a very small amount, so minimizing exposure to any dose
of ionizing radiation is a good idea.
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
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