Air kerma is the sum of kinetic energy of all charged particles liberated per unit mass. The unit is the joule per kilogram (J kg-1) and is given the special name gray (Gy). Air Kerma (Ka) is the radiation output rate that is measured in mR.
For X-rays with energies less than 300 kiloelectronvolts (keV), 1 Gy = 100 rad. In air, 1Gy of absorbed dose is delivered by 114 roentgens (R) of exposure.
- ↑ FDA. Mammography Quality Standards Act Regulations:definitions. http://www.fda.gov/Radiation-EmittingProducts/MammographyQualityStandardsActandProgram/Regulations/ucm110906.htm#s9002