放射性ヨウ素吸入時の甲状腺被曝線量と安定ヨウ素剤投与効果の感度解析

抄録

The prophylactic use of stable iodine is one of the protective measures during a nuclear emergency. In order to know the resultant radiation dose to the thyroid gland and the effectiveness of iodine prophylaxis in the case of Japanese, a sensitivity analysis was performed for related physiological parameters for Japanese. As a result, the variances in the deposition efficiency of radioactive iodine aerosol in the respiratory tract due to changes in the respiratory parameters were found rather small between the standard Caucasian and Japanese. The changes due to the radioactive iodine aerosol size were more significant, suggesting the importance of understanding the physico-chemical status of aerobic radioiodine released in a nuclear emergency. Concerning the metabolic parameters of iodine, the result of the sensitivity analysis based on an iodine metabolic model showed that the most critical parameters are those which describe the transport of stable and radioactive iodine from the blood compartment to the thyroid gland. Accordingly, a confirmation of the transport model and the related parameters for Japanese are essential to clarify the effectiveness of iodine prophylaxis to reduce thyroid gland exposure of Japanese. (This work was performed under the auspices of the Science and Technology Agency of Japan.)