Roentgen equivalent, man

The former (non-SI) unit of dose equivalent was the roentgen equivalent man (rem), which was defined in the same way as the sievert but with the absorbed dose in rad thus, 1 rem = 10 2 Sv. 

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). 

Rem (acronym for roentgen-equivalent man) The unit of dose of ionizing radiation that produces the same biological effect as a unit of absorbed dose of ordinary x-rays. 

REM (rem). A unit of dose equivalent in the field of radiation dosimetry. One rem equals the amount of ionizing radiation of any type which produces the same damage to humans as 1 roentgen of approximately 200 kilovolts x-radiation. (The unit is abbreviation of Roentgen Equivalent Man.)... 

The dose equivalent is the actual dose modified to take into account the different destructive powers of the various types of radiation in combination with various types of tissue. It is obtained by multiplying the actual dose (in rads) by the value of Q for the radiation type. The result is expressed in a unit called a roentgen equivalent man (rem) ... 

S02(g) in the extraction of copper, rock-salt structure A crystal structure the same as that of a mineral form of sodium chloride, roentgen equivalent man rem The unit for reporting dose equivalent. See also sievert. root (of an equation) The solutions of the equation f(x) = 0. See also Appendix IE. root mean square speed c The square root of the average value of the squares of the speeds of the molecules in a sample. 

Radiation, roentgen absorbed doses (RADs), and roentgen-equivalent man (REM) ... 

Rem This older term is the short abbreviation for roentgen equivalent man. It is defined as the dose of radiation absorbed, multiplied by a modifying factor called quality factor Q, or relative biological effectiveness, RBE that takes into account the type of radiation (of any kind) and how the radiation is absorbed. Thus, for beta, gamma and X-rays, the quality factor is 1 for alpha radiation it may be as high as 20, and for neutrons it varies from 3 to 10. 

Different types of radiation affect biological materials in different ways, so a different unit is needed to describe the dose necessary to produce an equivalent biological damage. Historically, this unit is the rem (roentgen-equivalent-man). The dose in rem is equal to the dose in rad multiplied by a quality factor, which varies with the type of radiation. For )3 -, y-, and X-ray radiation, the quality factor is 1 for neutrons, it is 2-11, depending upon the energy of the particle and for a-particles, the quality factor is 20. The SI unit for equivalent dose is the sievert (Sv), which is equivalent to 100 rem. 

The natural unit of dose equivalent is the rem roentgen equivalent man). 

RAM RBS rd RDE re re recryst red redn redox ref rel rel REL rem REM random access memory Rutherford backscattering spectrometry rad rotating disk electrode electron radius stereochemical descriptor (as in the re face) recrystallized reduced or reduction (in subscripts and superscripts) reduction reduction—oxidation reference relative relative (stereochemical descriptor) recommended exposure limit roentgen equivalent man rapid eye movement... 

Different kinds of radiation have different ionization efficiencies and are absorbed in different ways. In order to compensate for this the unit rem ( roentgen equivalent, man ) was introduced. It is defined as the quantity of radiation of any type which produces the same biological effect in man as that produced by 1 r of X-ray or y ray radiation. However, the biological effect depends upon the part of the body irradiated and on the type of radiation. This problem is dealt with by estimating a relative biological effectiveness (RBB), in relation to y-rays, for various parts of the body. For example, as far as the production of cataracts is concerned, 1 rad of fast neutrons is ten times as effective as 1 rad of y-rays. Thus if the eyes were... 

Roent- gen Relative biological effectiveness Radiation absorbed dose Roentgen equivalent man... 

Values of RBE for various types of radiation are listed in Table 10-1. The final unit of interest, the r m or roentgen equivalent man, is a true measure of the biological injury produced from various types of radiation. The dosage can be expressed in terms of units of total energy absorption multiplied by the relative biological effectiveness ... 

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