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The absorbed dose, measured in rad, is a better indicator of ARS. [3]: 592–593 A rem is a large dose of radiation, so the millirem (mrem), which is one thousandth of a rem, is often used for the dosages commonly encountered, such as the amount of radiation received from medical x-rays and background sources.
That model calculates an effective radiation dose, measured in units of rem, which is more representative of the stochastic risk than the absorbed dose in rad. In most power plant scenarios, where the radiation environment is dominated by X-or gamma rays applied uniformly to the whole body, 1 rad of absorbed dose gives 1 rem of effective dose. [5]
Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass.Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection (reduction of harmful effects), and radiology (potential beneficial effects, for example in cancer treatment).
In 1953 the International Commission on Radiation Units and Measurements (ICRU) recommended the rad, equal to 100 erg/g, as the unit of measure of the new radiation quantity absorbed dose. The rad was expressed in coherent cgs units. [5] In 1975 the unit gray was named as the SI unit of absorbed dose. One gray is equal to 1 J/kg (i.e. 100 rad).
The fundamental quantity is the absorbed dose (D), which is defined as the mean energy imparted [by ionising radiation] (dE) per unit mass (dm) of material (D = dE/dm) [8] The SI unit of absorbed dose is the gray (Gy) defined as one joule per kilogram. Absorbed dose, as a point measurement, is suitable for describing localised (i.e. partial ...
Relationship of ICRU/ICRP computed Protection dose quantities and units. The absorbed dose also plays an important role in radiation protection, as it is the starting point for calculating the stochastic health risk of low levels of radiation, which is defined as the probability of cancer induction and genetic damage. [8]
To help avoid confusion between these quantities, absorbed dose is measured in units of grays (in SI, unit symbol Gy) or rad (in CGS), while the others are measured in sieverts (in SI, unit symbol Sv) or rem (in CGS). 1 rad = 0.01 Gy and 1 rem = 0.01 Sv. [37]
Calculating equivalent dose from absorbed dose; =, where H T is the equivalent dose in sieverts (Sv) absorbed by tissue T, D T,R is the absorbed dose in grays (Gy) in tissue T by radiation type R and W R is the radiation weighting factor defined by regulation.