Answer to Question #13388 Submitted to "Ask the Experts"

Category: Radiation Basics

The following question was answered by an expert in the appropriate field:


Other than background radiation originating from natural sources, is there any way a person can live free from radiation exposure?


I shall assume that your question refers to ionizing radiation (e.g., gamma radiation, x rays, neutrons, beta radiation and alpha radiation) as opposed to nonionizing radiation such as electromagnetic radiation in the form of radio waves and microwaves. I also assume that within natural background radiation you mean to include naturally occurring radionuclides such as potassium-40 (40K), carbon-14 (14C) and radium-226 (226Ra) that get incorporated into some foods and subsequently eaten by human beings. I would be derelict in this discussion if I did not point out that, on average, the largest radiation dose from natural sources to an individual in this country comes from inhalation of radon gas, particularly radon-222 (222Rn), and a large part of this dose can be avoided by taking appropriate steps to minimize leakage of radon into one's home and/or by providing appropriate ventilation to reduce airborne radon in the home, usually best done by providing subfloor suction in the basement and directing exhaust outside the home. It is perhaps theoretically possible to exist with no or very minimal exposure to manmade sources of ionizing radiation, but this likely would be done at the cost of decreasing your prospects for a happy and healthy life.

The most significant sources of ionizing radiation exposure to human beings beyond natural background radiation involves the applications of radiation for medical purposes with diagnostic x rays being the greatest contributor. Very few of us go through life without being subjected to some such radiation. In most cases, diagnostic tests have a net health benefit in that they provide necessary information to guide further treatment. In many cases, such procedures are lifesaving. Similarly, tests in which man-made radioactive materials are introduced into the body to perform specific nuclear medicine diagnostic procedures may provide critical information that point the way to proper treatment, also sometimes lifesaving. Ionizing radiation is also used as a therapeutic agent to treat various forms of cancer, saving many lives and prolonging the lives of many patients.

Other notable man-made sources include such facilities as nuclear reactors and high-energy accelerators that produce a variety of radiations and radioactive materials. Small amounts of radiation, such as gamma rays and neutrons may leak through radiation shielding materials and produce very low radiation levels outside a reactor or an accelerator building, and small amounts of radioactive materials may leak from some systems and possibly enter the air or water environment around the facility. People who live close to such facilities may experience a tiny increase in radiation exposure beyond the natural background. While such exposures are typically negligible in terms of any heath impact, they could be eliminated by an affected person relocating to a greater distance from the facility if one were so inclined. Except for a possible situation in which a severe accident might take place, and large amounts of radiation and radioactivity might get released from a facility, the doses to individual members of the public, even those living close to the facility, from operation of nuclear facilities are typically so small as to be deemed negligible in health risk. Doses to members of the public living at significant distances from such facilities would naturally be even smaller.

Most people are also exposed to very small amounts of radiation from various consumer products. One such ubiquitous product is the typical smoke detector, which incorporates a small radioactive source of americium, americium-241 (241Am), which emits some very low intensity gamma radiation, some of which can penetrate the housing of the detector. Other products such as self-luminous dial watches that employ radiations from radioactive material incorporated into the paint to activate a luminescent phosphor are also potential sources of very low exposure. While one might elect not to use such watches, one would be accepting an unnecessary risk from potential fire to eliminate the use of smoke detectors in the interest of minimizing an already negligible risk from radiation.

The end conclusion I would offer is that elimination of man-made radiation exposure is not only impractical but, more importantly, unhealthy. However, exposures that offer no real benefit and can be controlled may be logical targets for elimination. In this regard, medical applications of radiation are the areas where it might be possible to produce the greatest reduction in man-made radiation exposures. In a situation where minimal or negligible benefits are likely a particular exposure may not be warranted. For example, the use of dental x rays may sometimes be overdone, especially in patients who do not exhibit any symptoms of tooth problems and do not have a history that dictates a need for x rays. Whenever a diagnostic test is recommended by a physician, the patient should make sure he or she knows why it is being recommended, what is to be gained from having the procedure, what are the consequences of not having the procedure, and what are possible alternatives to the procedure.

I hope this has been helpful to you.

George Chabot, PhD

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
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