Roentgen (unit) Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays. It is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air. In 1928 it was the first international measurement quantity for ionising radiation to be defined for radiation protection, and was an easily replicated method of measuring air ionization directly by using an ion chamber. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays. Although relatively easy to measure, it had
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)