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
Sanford Burnham Prebys Medical Discovery Institute careers in basic and translational research through a curriculum of focused, multi-disciplinary instruction. In 2015, SBP achieved accreditation with the Western Association of Schools and Colleges. SBP also employs postdoctoral fellows; there are typically around 250 postdocs training at SBP at any time. The endowment was recorded at as low as $15.2 million, a 13 percent drop from nearly $17.5 million in February 2008, due largely to losses on investments. Its endowment stood at $22.5 million as of Dec. 31, 2009. Sanford Burnham Prebys Medical Discovery Institute Sanford Burnham Prebys Medical Discovery Institute (SBP) is a non-profit medical research institute