Issues in radiation dose measurement using electronic personal dosimeters during disaster relief activities

In this study, we measured the radiation exposure of the medical relief team of the Japanese Red Cross Society (JRCS) members during the Noto Peninsula earthquake using electronic personal dosimeters (EPDs) and investigated the frequency of electromagnetic interference (EMI) events that caused abnormally high dose readings.

Six JRCS medical relief team members (two physicians, three nurses, and one logistics officer) involved in the Noto Peninsula earthquake disaster relief activities were provided with EPDs to measure their radiation exposure during the activity period. A background radiation dosimeter was also installed on-site to record ambient radiation levels.

Over 2.5 days of disaster relief activities, the background radiation dose was 3.0 ± 3.0 μSv. However, the highest recorded dose among the team members was 2075.0 ± 207.5 μSv for a nurse, while the average dose for the other members was 40.0 ± 39.5 μSv. A significant radiation dose was observed despite no radioactive material dispersion.

Among the four individuals who exhibited abnormally high dose readings, three were operating digital devices at the time of measurement, suggesting a strong likelihood that electromagnetic interference was the cause. The effective management of radiation doses using EPDs during nuclear disasters requires the implementation of countermeasures against EMI from digital devices.