- The SI unit of ionizing radiation effective dose, equal to the absorbed dose in gray, weighted for both the quality of radiation in question and the tissue response to that radiation. The unit is the joule per kilogram and 1 Sv = 100 rem. See effective dose, equivalent dose.
* * *Sievert Rolf Maximilian (1896-1966)Swedish physicist. Sievert was a pioneer in radiation physics and protection from radiation. He served as head of the physics laboratory at Sweden's Radiumhemmet from 1924 to 1937, when he became head of the department of radiation physics at the Karolinska Institute. He played a pioneering role in the measurement of doses of radiation especially in its use in the diagnosis and treatment of cancer. In later years he focused his research on the biological effects of repeated exposure to low doses of radiation. In 1964 he founded the International Radiation Protection Association, serving for a time as its chairman. He also chaired the United Nations Scientific Committee on the Effects of Atomic Radiation. In 1979 a scientific conference named a unit for the dosage of ionizing radiation in his honor.
* * *n.the SI units of dose equivalent, being the dose equivalent when the absorbed dose of ionizing radiation multiplied by the stipulated dimensionless factors is 1 J kg-1. As different types of radiation cause different effects in biological tissue a weighted absorbed dose, called the dose equivalent, is used in which the absorbed dose is modified by multiplying it by dimensionless factors stipulated by the International Commission on Radiological Protection. The sievert has replaced the rem. Symbol: Sv.
* * *sie·vert (Sv) (seґvərt) the SI unit of radiation absorbed dose equivalent, defined as that producing the same biologic effect in a specified tissue as 1 gray of high-energy x-rays; 1 sievert equals 100 rem.
Medical dictionary. 2011.