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
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