Implementation of ICRP 116 Dose Conversion Coefficients for Reconstructing Organ Dose in a Radiation Compensation Program.

Since 2000, National Institute for Occupational Safety and Health (NIOSH) has used dose conversion coefficients published by the International Commission on Radiation Protection in report 74 (ICRP 74) to determine organ dose from external radiation sources. In 2010, the ICRP issued publication 116 using more realistic phantoms than ICRP 74. NIOSH has developed a Monte Carlo method to sample the energy-organ-specific distribution of the ICRP 116 conversion coefficients to determine the organ dose and the associated uncertainty. Using Monte Carlo methods, irradiation geometry factors (IGFs) were developed to convert the measured dosemeter dose on the front of the body to values that are compatible with ICRP 116 organ dose conversion coefficients. Specific IGFs were developed for (1) both neutrons and photon exposures, (2) to male and female workers and (3) for rotational and isotropic exposure geometries. The computed mean organ dose and the associated uncertainty are used in the probability of causation calculation for compensation.