Roentgen (unit) this derivative quantity the roentgen equivalent physical (rep) to distinguish it from the ICR roentgen. The introduction of the roentgen measurement unit, which relied upon measuring the ionisation of air, replaced earlier less accurate practices that relied on timed exposure, film exposure, or fluorescence. This led the way to setting exposure limits,and the National Council on Radiation Protection and Measurements of the United States established the first formal dose limit in 1931 as 0.1 roentgen per day. The International X-ray and Radium Protection Committee, now known as the International Commission on Radiological Protection (ICRP) soon followed with a limit of
Carl August Wilhelm Berends junger Ärzte am Krankenbett" (Education of Young Physicians at the Bedside), in which he described his experiences at the Thielschen Krankenhaus in Frankfurt. Shortly after his death in 1826, his one-time student, Karl Sundelin, published Berends' lectures on practical medical science (""Vorlesungen über die praktische Arzneiwissenschaft""). Carl August Wilhelm Berends Carl August Wilhelm Berends (April 19, 1759 – December 1, 1826) was a German physician born in Anklam, Pomerania. He studied medicine at Viadrina University in Frankfurt an der Oder, where in 1788 he became a professor of medicine. In 1811 he moved to the University of Breslau, being due