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 In 2007, T. Denny Sanford gave the Institute $20 million through Sanford Health, a hospital which received significant donations from T. Denny Sanford previously, allowing it to create the Sanford Children's Health Research Center, which has sites in Sioux Falls, South Dakota and La Jolla, CA, the latter within the campus of SBP. In 2010, the Institute adopted the name Sanford-Burnham Medical Research Institute following a $50 million pledge of support from Sanford. An anonymous gift of $275 million was made in 2014. In 2015, the Institute changed its name again to Sanford Burnham Prebys Medical Discovery Institute following a