Physics Athens 2016

KERMA vs Absorbed Dose

KERMA : K inetic E nergy R eleased per unit Ma ss (J/kg = Gy) Sum of initial kinetic energies transferred from indirectly ionizing radiation (  ) to charged particles (e - ) in a sample of matter

Absorbed Dose : energy absorbed per unit mass (J/kg = Gy) Mean energy transfer imparted by ionizing radiation to matter within volume V

→ E(entering V) – E(leaving V)

absorption of energy does not take place at same location as energy transfer by KERMA → electrons travel in the medium and deposit energy along their tracks, the subsequent imparting of energy to matter ( absorbed Dose ) is spread over distances determined by the ranges of charged particles