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The relative biological effectiveness can help give a better measure of the biological effect of radiation. The relative biological effectiveness for radiation of type R on a tissue is defined as the ratio = where D X is a reference absorbed dose of radiation of a standard type X, and D R is the absorbed dose of radiation of type R that causes ...
There is no universally applicable conversion constant from rad to rem; the conversion depends on relative biological effectiveness (RBE). The rem has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States.
The Röntgen equivalent physical (rep), introduced by Herbert Parker in 1945, [12] was the absorbed energetic dose to tissue before factoring in relative biological effectiveness. The rep has variously been defined as 83 or 93 ergs per gram of tissue (8.3/9.3 mGy) [13] or per cc of tissue. [14]
Many studies have attempted to relate linear energy transfer to the relative biological effectiveness (RBE) of radiation, with inconsistent results. The relationship varies widely depending on the nature of the biological material, and the choice of endpoint to define effectiveness.
Although the CIPM definition states that the linear energy transfer function of the ICRU is used in calculating the biological effect, the ICRP in 1990 [15] developed the "protection" dose quantities named effective and equivalent dose, which are calculated from more complex computational models and are distinguished by not having the phrase ...
W R (formerly 'Q' factor) is a factor that scales the biological effect for different types of radiation, relative to x-rays (e.g. 1 for beta radiation, 20 for alpha radiation, and a complicated function of energy for neutrons). In general, conversion between rates of emission, the density of radiation, the fraction absorbed, and the biological ...
Organs that are remote from the site of irradiation will only receive a small equivalent dose (mainly due to scattering) and therefore contribute little to the effective dose, even if the weighting factor for that organ is high. Effective dose is used to estimate stochastic risks for a ‘reference’ person, which is an average of the population.
The field of Health Physics is related to the field of medical physics [3] and they are similar to each other in that practitioners rely on much of the same fundamental science (i.e., radiation physics, biology, etc.) in both fields. Health physicists, however, focus on the evaluation and protection of human health from radiation, whereas ...