Roentgen (unit) One roentgen deposits of absorbed dose in dry air, or in soft tissue. One roentgen of X-rays may deposit anywhere from in bone depending on the beam energy. This tissue-dependent conversion from kerma to absorbed dose is called the F-factor in radiotherapy contexts. The conversion depends on the ionizing energy of a reference medium, which is ambiguous in the latest NIST definition. The roentgen has its roots in the Villard unit defined in 1908 by the American Roentgen Ray Society as "the quantity of radiation which liberates by ionisation one esu of electricity per cm of air under normal conditions
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)