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
Albany Medical College co-founder of the American Medical Association. AMC is attributed as the site where David S. Sheridan perfected the modern-day disposable catheter, among other major discoveries and innovations. Among AMC alumni accomplishments include the discovery of the hormone leptin, the invention of computed tomography, and the discovery of oral rehydration therapy. There are multiple courses of study at the College, with tracks that end in an MD degree, as well as a Graduate Studies program with the following departments: AMC sponsors medical residency programs in anesthesiology; emergency medicine; family medicine; internal medicine; medicine/pediatrics; neurology; obstetrics, gynecology, and reproductive sciences; ophthalmology; pathology;