NCIt definition : A unit of exposure to ionizing radiation in CGS system. One roentgen is the amount
of gamma or x-rays required to produce ions resulting in a charge of 2.58E-4 coulombs/kilogram
of air under standard conditions.;
Alternative definition : CDISC: A unit of exposure to ionizing radiation. One Roentgen is the amount of gamma
or x-rays required to produce ions resulting in a charge of 2.58E-4 Coulombs/kilogram
of air under standard conditions.(NCI);