Exposure is the charge produced in air from ionization by gamma and x-rays and measured in roentgen (R) or Coulombs per kilogram of air, C/kg.
Absorbed dose describes the energy deposited by any form of ionizing radiation in a unit mass of material. Absorbed dose is measured in rad or Gray (Gy), where 1 Gy = 100 rad.
Dose Equivalent is the energy deposited in human tissue, modified by a factor that accounts for the “quality” of the absorbed radiation. Dose equivalent is measured in rem or Sievert (Sv), where 1 Sv = 100 rem.
Beta particles and photons from x-rays and gamma rays have a quality factor of 1, meaning an absorbed dose is the same as the equivalent dose (1 rad = 1 rem)
Alpha particles have a quality factor of 20, so the equivalent dose is 20x the absorbed dose (1 rad = 20 rem)
