Air-kerma, incident

In diagnostic radiology, this is the air kerma from the incident beam on the central x-ray beam axis at focal spot-to-skin distance (i.e. at skin entrance plane) without backscatter. Incident air-kerma can be calculated from the x-ray tube output, where output is measured using a calibrated ionising chamber. (Adapted from ICRP Publication 117, 2010)

ICRP Glossary entry - May 2019