We live in a radioactive world - humans always have. Radiation is part of our natural environment. We are exposed to radiation from materials in the earth itself, from naturally occurring radon in the air, from outer space, and from inside our own bodies (as a result of the food and water we consume). This radiation is measured in units called millisieverts (mSv).
The average dose per person from all sources is about 6.20 mSv per year. It is not, however, uncommon for any of us to receive less or more than that in a given year (largely due to medical procedures we may undergo). International Standards allow exposure to as much as 50 mSv a year for those who work with and around radioactive material.
* Average values.
** Some of the radiation sources listed in this chart result in an exposure to only one part of the body. For example, false teeth and crowns result in a radiation dose to the mouth. The annual dose numbers given here represent the "effective dose" to the whole body.
The value is less than 1, but adding a value of 1 would be reasonable.
Exposures for medical tests vary depending upon equipment and the patient. The doses listed are an average for an actual exposure.
How is radiation measured? The units used to measure radiation are the rem and the millirem (1/1,000th of a rem). The international unit for measuring radiation exposure is the sievert (Sv), and 1 Sv = 100 rems. Therefore, to convert from the mrem values above to mSv (millisievert), divide the value by 100.
Primary sources for this information are National Council on Radiation Protection and Measurements Reports: #92 Public Radiation Exposure from Nuclear Power Generation in the United States (1987); #93 Ionizing Radiation Exposure of the Population of the United States (1987); #94 Exposure of the Population in the United States and Canada from Natural Background Radiation (1987); #95 Radiation Exposure of the U.S. population from Consumer Products and Miscellaneous Sources, (1987); #100 Exposure of the U.S. Population from Diagnostic Medical Radiation (1989); and #160 Ionizing Radiation Exposure of the Population of the United States (2009).
Last updated June 12, 2012, 2:24pm CDT.