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Human exposure to radioactivity

Based on an evaluation of the radiation sources in France, the country’s population is exposed to an estimated total dose of 3.5 mSv per year, including 2 mSv from natural sources and 1.5 mSv of artificial origin. These figures are averages and can vary according to a number of parameters, such as geographic location.
Natural radiation sources account for about 60% of our total exposure to radioactivity. Most natural radiation is due to radon, a radioactive gas produced by uranium and released by rocks. The remainder comes from telluric radiation emitted by rocks, cosmic rays and the human body’s own radioactivity due to the biological presence of two naturally occurring radioactive elements, potassium-40 and carbon-14.
We are all constantly exposed to natural radioactivity. However, spread out over the days, months and years, its dose rate is low.
Medical analyses and treatments make up 99% of artificial radiation exposure. The remaining 1% is produced by industry, nuclear fallout, nuclear installations and research. It is difficult to reduce these doses other than by improving the equipment involved. Foregoing the examinations and radiation therapy made possible by nuclear medicine would mean turning our backs on the advances of modern medical science.
Even so, radiation is recommended only when its potential benefits outweigh the risks. When radiation is justified, physicians try to use it as efficiently as possible, using a set of Diagnostic Reference Levels (DRL) to limit the doses in relation to the therapeutic goal.
X-ray medical imaging produces the highest levels of human radiation exposure.
However this is not, properly speaking, an example of radioactivity since X-rays are not produced by nuclear reactions but rather by the electronic excitation of atoms.