After the accident at Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Station (FDNPS) in 2011, many hospitalized older patients died during or after evacuation. In this study, with the aim of exploring the concept of “tailor-made” evacuations considering individual situations after a nuclear disaster, we estimated ambient dose equivalent rate (H*(10)) data from shortly after the accident and calculated exposure doses of hospitalized patients and medical personnel in several scenarios.

We used data from the Yamada district, which is located almost 4 km from the FDNPS and near 3 hospitals in which many patients died during or after evacuation. We created 10 simulation models considering differences in residential area, working hours, and distance from the workplace.

On March 15, 2011, H*(10) rapidly increased by more than 250 μSv/hour before steadily decreasing and reaching less than 50 μSv/hour 1 month later. None of the accumulated exposure doses in Models 1-3 reached 20 mSv. In Model 3 (hospitalized patients), the accumulated exposure doses were much less than 10 mSv.

To minimize disaster-related incidents after a nuclear disaster, the present findings highlight the importance of establishing the concept of “tailor-made” evacuations considering individual situations.