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
Friedrich Wilhelm Theile addition to his own writings, he translated several works by foreign physicians and scientists — Louis Delasiauve, Franciscus Cornelis Donders, Auguste Ambroise Tardieu, Pieter Harting and Jacobus Schroeder van der Kolk. Friedrich Wilhelm Theile Friedrich Wilhelm Theile (11 November 1801, in Buttstädt – 20 October 1879, in Weimar) was a German physician and anatomist. In 1825 he received his medical doctorate from the University of Jena with the dissertation-thesis "De Musculis nervisque laryngeis". From 1828, with Heinrich Wilhelm Ferdinand Wackenroder, he was in charge of the pharmaceutical institute at Jena. In 1831 he became an associate professor, and three years