Radiation relative biological effectiveness

Q is the relative biological effectiveness of the radiation. Normally, Q < 1 Sv-Gy 1 for 7, P, and most other radiation, but Q < 20 Sv Gy 1 for a radiation and fast neutrons. A further factor of 5 (that is, 5Q) is used for bone under certain circumstances. 

Distinguish a, (3, and -y radiation by their response to an electric field, penetrating power, and relative biological effectiveness (Sections 17.1 and 17.6). 

Biologic Effectiveness of Radiation—See Relative Biological Effectiveness. 

Dose Equivalent (DE)—A quantity used in radiation safety practice to account for the relative biological effectiveness of the several types of radiation. It expresses all radiations on a common scale for calculating the effective absorbed dose. It is defined as the product of the absorbed dose in rad and certain modifying factors. (The unit of dose equivalent is the rem. In SI units, the dose equivalent is the sievert, which equals 100 rem.)... 

Relative Biological Effectiveness (RBE)—The RBE is a factor used to compare the biological effectiveness of absorbed radiation doses (i.e., rad) due to different types of ionizing radiation. More specifically, it is the experimentally determined ratio of an absorbed dose of a radiation in question to the absorbed dose of a reference radiation (typically 60Co gamma rays or 200 keV x rays) required to produce an identical biological effect in a particular experimental organism or tissue (see Quality Factor). 

Relative biological effectiveness (RBE) The biological effectiveness of any type of ionizing radiation in producing a specific damage (i.e., leukemia, anemia, carcinogenicity). See Radiation dose. 

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). 

B.5.2 Relative Biological Effectiveness.The term relative biologic effectiveness (RBE) is used to denote the experimentally determined ratio of the absorbed dose from one radiation type to the absorbed dose of a reference radiation required to produce an identical biologic effect under the same conditions. Gamma rays from cobalt-60 and 200 to 250 KeV X-rays have been used as reference standards. The term RBE has been widely used in experimental radiobiology, and the term quality factor used in calculations of dose equivalents for radiation protection purposes (ICRP 1977 NCRP 1971 UNSCEAR 1982). The generally accepted values for RBE are provided in Table B-4. 

Somatic Radiation Dose for the General Population, Report of the Ad Hoc Committee of the National Council on Radiation Protection and Measurements, 6 May 1959, Science, February 19, 1960, Vol. 131, No. 3399, pages 482-486 Dose Effect Modifying Factors in Radiation Protection, Report of Subcommittee M-4 (Relative Biological Effectiveness) of the National Council on Radiation Protection and Measurements,... 

The National Coimdl on Radiation Protection and Measurements (NCRP) has been concerned from its inception with assessment of the risks of low-level irradiation. In recent years, this concern has prompted increasingly detailed efforts to quantify the influence of dose, dose rate, and linear energy transfer (LET) on the biomedical effects of radiation, with particular reference to the carcinogenic risks of low-level exposure (NCRP, 1980) and the work-in-progress of NCRP Sdentific Committee 40 on LET and relative biological effectiveness. 

Relative Biological Effectiveness (RBE) Factor used to compare the biological effectiveness of different types of ionizing radiation inverse ratio of the amount of absorbed radiation required to produce a given effect to a standard radiation required to produce the same effect. 

FIGURE 7. Dependence of relative biological effect (RBE) and of oxygen enhancement ratio (OER) on the linear energy transfer (LET) of radiation. Reprinted from Brown, Appl. Radiat. Isot., 37, 789 (1986) (Reference 84) by kind permission of Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, OX5 1GB... 

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. 

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