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内容記述 |
One of the componets of the Fukushima Health Management Survey(FHMS) is the Basic Survey, which estimates individual extenal doses for the first months after the 2011 nuclear power plant aciident. However, external exposure continues long-term. According to estimations by international organizations, the external dose during the first year accountts for a significant part of the long-term dose. Thus, the present study was intended to estimate the first-year doses by extrapolating the Basonc Survey results. For the most municopalities of non-evacuated areas, ambient dose rate had been continuosly measured for at least one designated point in each municipality after the accident. In the present study, a unicipality-average dose receaved by residents for a period was assumed to be proportional to the ambient dose measured at the desinged point of that municipality during the same period. Based on this asssumption. 4-month, municipality-avarage doses calculated from the Basic Survey results were extrapolated to ontain first-year doses. The extrapolated first-year doses for 49 municipalities in the non-evacuated areas had a good correlation with those estimated by UNSCEAR, although the extraplated doses were generally higher (slope of teh regression line: 1.23). The extrapolated municipality-average doses were in reasonable agreement ( within 30%) weth personal dosimeter measurement, suggesting that the extrapolation was reasonable. The present paper reports the first 4-month average dose for all 59 municipalities of Fukushima Prefecture and the extrapolated first-year doses for 49 municipalities. The extrapolated doses will be the basis for future epidemiological studies related to the FHMS. |
