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
Anton Wilhelm Plaz Anton Wilhelm Plaz Anton Wilhelm Plaz (1 January 1708, Leipzig – 26 February 1784, Leipzig) was a German physician and botanist. From 1723 he studied medicine at the universities of Leipzig and Halle, receiving his doctorate at the latter institution in 1728. In 1733 he became an associate professor of botany at Leipzig, where afterwards, he successively served as a full professor of botany (1749–54), physiology (1754–58), anatomy and surgery (1758), pathology (1758–73) and therapy (1773–84). From 1773 to 1784 he was dean to the medical faculty at the university. He was a member of the Römisch Kaiserlichen Akademie der