Ionizing radiation sievert

Roentgen equivalent man (rem) The amount of ionizing radiation of any type that produces the same damage to humans as 1 roentgen of radiation. One rem = 1 roentgen equivalent physical (rep)/relative biological effectiveness (RBE). In the latest nomenclature, 100 rem = 1 Sievert (Sv). 

A unit of dose equal to the amount of ionizing radiation that produces in humans the same biological effect as one rad of X-rays or gamma rays. One rem is equal to 0.01 sievert. 

For radiation protection purposes, several theoretical dosimetric quantities have been created that attempt to normalize the responses of different tissues and organs of the body from irradiation by different types of ionizing radiation so that uniform radiation protection guidelines can be promulgated that are insensitive to the particulars of any given irradiation scenario. The traditionally used quantity has been the dose equivalent (DE), which is defined as the absorbed dose (D) multiplied by the quality factor Q. The unit of dose equivalent has been the rem, which is dimensionally the same as the rad the SI unit is the Sievert (Sv). Recently, the DE has been replaced by a similar concept called the equivalent dose. The equivalent dose depends on the relative biological effectiveness rather than on Q. 

Mostly natural sources contribute to the ionizing radiation exposure that people undergo aU the time. The received dose of radiation is measured in grays. The absorbed dose of radiation that results in damage done to organisms is measured in sieverts. 

Similarly, in the field of ionizing radiation, the SI unit of activity is designated as the becquerel (Bq) rather than the reciprocal second (s ), and the SI units of absorbed dose and dose equivalent are designated as the gray (Gy) and the sievert (Sv), respectively, rather than the joule per kilogram (J/kg). 

REM is the dosage of any ionizing radiation that will cause biological injury to human tissue equal to the injury caused by one roentgen of x-ray or gamma ray dosage with 1 rem is equivalent to 0.01 Sievert (Sv). 

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