Abstract
The occurrence of epilation among the atomic bomb survivors in Hiroshima and Nagasaki has been discussed as a symptom for acute radiation syndrome. Epilation was also reported among "early entrance survivors" who were located far away from the hypocenter at the time of the atomic bomb explosion and entered the exposed area later. Considering that the early entrants were exposed to negligibly small dose by the initial neutron and γ rays due to fission reaction of the atomic bomb, the dose on such survivors was supposed to be mainly caused by radiation from neutron-activated materials around the ground. Therefore, in order to ascertain whether or not the epilation among the early entrants was caused by radiation, it is essential to evaluate absorbed dose to skin by the radionuclides produced in soil via activation by the atomic bomb neutrons.
Both &beta and γ rays can contribute to skin dose though only γ rays has been considered in the conventional atomic bomb dosimetry such as T65D, DS86 and DS02. In the case where radionuclides are deposited on skin surface, rather high dose could be delivered to skin tissue by β rays than by γ rays. The present study, therefore, evaluates the absorbed dose in two types of skin exposure, i.e., exposure from radionuclides in the ground soil and exposure from soil contamination on skin surface. Preliminary results are shown for early entrants in Hiroshima.
