Radiation-Related Posterior Lenticular Opacities in Hiroshima and Nagasaki Atomic Bomb Survivors Based on the DS86 Dosimetry System

This paper investigates the quantitative relationship of ionizing radiation to the occurrence of posterior lenticular opacities among the survivors of the atomic bombings of Hiroshima and Nagasaki suggested by the DS86 dosimetry system. DS86 doses are available for 1983 (93.4%) of the 2124 atomic bomb survivors analyzed in 1982. The DS86 kerma neutron component for Hiroshima survivors is much smaller than its comparable T65DR component, but still 4.2-fold higher (0.38 Gy at 6 Gy) than that in Nagasaki (0.09 Gy at 6 Gy). Thus, if the eye is especially sensitive to neutrons, there may yet be some useful information on their effects, particularly in Hiroshima. The dose-response relationship has been evaluated as a function of the separately estimated γ-ray and neutron doses. Among several different dose-response models without and with two thresholds, we have selected as the best model the one with the smallest χ² or the largest log likelihood value associated with the goodness of fit. The best fit is a linear γ-linear neutron relationship which assumes different thresholds for the two types of radiation. Both γ and neutron regression coefficients for the best fitting model are positive and highly significant for the estimated DS86 eye organ dose.