DefinitionThis section has been translated automatically.
X-ray (R) = unit of the ion dose. It corresponds to a quantity of radiation which produces 2 ×109 ion pairs in 1,293 mg (= 1 cm3) of air. This quantity of ions can transport a charge from an electrostatic unit (= 3,33 × 10-10 coulombs), unit: coulomb/kg. Rad (radiation absorbed dose) represents the unit of radiation absorbed in a tissue. 1 rad corresponds to the absorption of 100 ergs of energy (or about 1 R/g of tissue). For soft tissue, 1 R is equivalent to about 1 rad. The unit Gray (Gy) corresponds to 100 rad. It was introduced to replace rad.
Prof. Dr. med. Peter Altmeyer