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
Dietrich Wilhelm Heinrich Busch Dietrich Wilhelm Heinrich Busch Dietrich Wilhelm Heinrich Busch (16 March 1788 – 15 March 1858) was a German obstetrician born in Marburg. In 1806 he earned his medical doctorate at the University of Marburg, becoming an associate professor of surgery in 1814. In 1817 he was appointed professor of obstetrics at Marburg, where from 1820 to 1829 he was director of the department of obstetrics. In 1829 he succeeded Adam Elias von Siebold (1775-1828) as professor and director of the obstetrics clinic at Friedrich Wilhelm University in Berlin, serving as university rector in 1835/36. He would remain as director of