Thyroid Doses in Children from Radioiodine following the Accident at the Fukushima Daiichi Nuclear Power Plant

Abstract

Background: Huge amounts of radionuclides were released into the environment due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, which caused not only serious contamination on the ground, but also radiation exposure to the public. One problem that remains in performing the dose estimation is the difficulty of estimating the internal thyroid dose due to the intake of radioiodine (mainly, 131 I) because of limitations to the human data available. Materials and Methods:The relevant papers were collected and reviewed by the authors. The results of thyroid dose estimates from different studies were tabulated for comparison. Results and Discussion:The thyroid dose estimates from the studies varied widely. The dose estimates by the United Nations Scientific Committee on the Effects of Atomic Radiation were higher than the others due to the ingestion dose being based on conservative assumptions. The dose estimates by Japanese experts were mostly below 20-30 mSv. The recent studies suggested that exposure on March 12, 2011 would be crucial for late evacuees from the areas near the FD-NPP because of the possible intake of short-lived radionuclides other than 131 I. Further multilateral studies are vital to reduce uncertainties in the present dose estimations. Conclusion:The estimation of the thyroid doses to Fukushima residents still has many uncertainties. However, it is considered unlikely that the thyroid doses exceeded 50 mSv except in some extreme cases. Further multilateral studies are thus necessary to reduce the uncertainties in the present dose estimations.

Estimation of the Early Cs-137 Intake of Evacuees from Areas Affected by the 2011 Fukushima Daiichi Nuclear Power Plant Accident Based on Personal Behavioral Data and the Latest Atmospheric Transport and Dispersion Model Simulation

“…The results of the research during this 9-y period indicated that the estimated radiation doses to the residents were to be low in general, and the residents' future radiation-induced risk was considered low (UNSCEAR 2014). However, as we have pointed out (Kim et al 2016a and c; Kim et al 2020; Kim and Kurihara 2020), further studies are still needed to improve the dose assessment; in particular, the dose assessment for internal thyroid exposure from the short-lived radionuclides (e.g., 131 I, 132 Te- 132 I, and 133 I). The greatest obstacle has been the shortage of direct human measurements at the early phase when the traces of 131 I (the main contributor to the internal thyroid dose) were detectable.…”

Estimation of the Thyroid Equivalent Doses to Residents in Areas Affected by the 2011 Fukushima Nuclear Disaster Due to Inhalation of 131I Based on Their Behavioral Data and the Latest Atmospheric Transport and Dispersion Model Simulation

“…After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011, a great effort has been made to assess the radiation exposure doses of residents of Fukushima Prefecture by many Japanese scientists and international bodies (Ishikawa 2017, 2020; Kurihara 2018; Kim and Kurihara 2020; WHO 2012; UNSCEAR 2014; IAEA 2015). These results would provide the scientific basis to estimate the future radiation-associated health effects of the prefecture's residents.…”