Roentgen equivalent man has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States. A number of earlier definitions going back to 1945 were derived from the roentgen unit, which was named after Wilhelm Röntgen, a German scientist who discovered X-rays. The acronym is now a misleading historical artifact, since 1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem. One rem carries with it a 0.05% chance of
Wilhelm Alexander Freund Wilhelm Alexander Freund Wilhelm Alexander Freund (August 26, 1833 - December 24, 1917) was a German gynecologist who was a native of Krappitz, Silesia. Born into a Jewish family, in 1855 he earned his medical degree at the University of Breslau, afterwards practicing gynecology in the same city. In 1874 he became an associate professor at Breslau. In 1879 he relocated to Strasbourg, where he served as a professor of gynecology and obstetrics. He died in Berlin. In January 1878, Freund performed the first abdominal extirpation of a cancerous uterus. Twenty years later in 1898, Austrian gynecologist Ernst Wertheim (1864-1920)