Conversion coefficients calculation of mono-energetic photons from air-kerma using Monte Carlo and analytical methods

Abstract

This study is aimed to calculate the conversion coefficients H∗(10)/Φ form air-kerma for beams of mono-energetic photons, which incident on ICRU sphere diameter 30 cm of ICRU tissues material with a density of 1 g/cm3 four-element tissue and a weight composition of 76.2% oxygen, 11.1% carbon, 10.1% hydrogen and 2.6% nitrogen (ICRU 57, 1997). The conversion coefficients are calculated using two methods: the DOSRZnrc based on EGSnrc code (Kawrakow et al., 2017) and our developed FORTRAN subroutine which evaluates the analytical expression available from a fit to Monte Carlo calculations (Veinot and Hertel, 2011). Our results have been carried out for absorbed dose and kerma approximations, for mono-energetic photons from 15 keV to 10 MeV. The results obtained were compared to those published by ICRU reports (ICRP Publication 74, 1996; ICRU 57, 1997). A good agreement with reference data with a local difference less than 2% was found. Keywords: Ambient dose equivalent, Air-kerma, Conversion coefficients, EGSnrc, FORTRAN