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Background radiation is defined by the International Atomic Energy Agency as "Dose or the dose rate (or an observed measure related to the dose or dose rate) attributable to all sources other than the one(s) specified. [1]
The definition of the BRET unit is apparently unstandardized, and depends on what value is used for the average annual background radiation dose, which varies greatly across time and location. The 2000 UNSCEAR estimate for worldwide average natural background radiation dose is 2.4 mSv (240 mrem), with a range from 1 to 13 mSv. A small area in ...
The worldwide average background dose for a human being is about 3.5 mSv per year , mostly from cosmic radiation and natural isotopes in the earth. The largest single source of radiation exposure to the general public is naturally occurring radon gas, which comprises approximately 55% of the annual background dose.
Background radiation is from naturally radioactive materials and cosmic radiation from space. [5] People are exposed to this radiation from the environment continuously, with an annual dose of about 3 mSv. [5] Radon gas is a radioactive chemical element that is the largest source of background radiation, about 2mSv per year. [17]
D T,R is the absorbed dose in tissue T by radiation type R and W R is the radiation weighting factor defined by regulation. Thus for example, an absorbed dose of 1 Gy by alpha particles will lead to an equivalent dose of 20 Sv. The radiation weighting factor for neutrons has been revised over time and remains controversial. This may seem to be ...
For comparison, radiation levels inside the United States Capitol are 85 mrem/yr (0.85 mSv/yr), close to the regulatory limit, because of the uranium content of the granite structure. [14] The NRC sets the annual total effective dose of full body radiation, or total body radiation (TBR), allowed for radiation workers 5,000 mrem (5 rem). [15] [16]
Effective dose is a dose quantity in the International Commission on Radiological Protection (ICRP) system of radiological protection. [1]It is the tissue-weighted sum of the equivalent doses in all specified tissues and organs of the human body and represents the stochastic health risk to the whole body, which is the probability of cancer induction and genetic effects, of low levels of ...
The concept of radiation hormesis is relevant to this table – radiation hormesis is a hypothesis stating that the effects of a given acute dose may differ from the effects of an equal fractionated dose. Thus 100 mSv is considered twice in the table below – once as received over a 5-year period, and once as an acute dose, received over a ...