This is a summary of the nuclear accident at the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Stations (FDNPS) on 11 March 2011 to be used as a review of the radiation effects to the thyroid and strategies of prevention.
The amount of radioiodine released to the environment following the Fukushima accident was 120 Peta Becquerel, which is approximately one-tenth of that in the Chernobyl accident. Residents near the FDNPS were evacuated within a few days and foodstuffs were controlled within 1 or 2 weeks. Therefore, thyroid radiation doses were less than 100 mSv (intervention levels for stable iodine administration) in the majority of children, including less than 1 year olds, living in the evacuation areas. Because the incidence of childhood thyroid cancer increased in those residing near the site following the Chernobyl accident, thyroid screening of all children (0–18 years old) in the Fukushima Prefecture was started. To date, screening of more than 280 000 children has resulted in the diagnosis of thyroid cancer in 90 children (approximate incidence, 313 per million). Thus, although the dose of radiation was much lower, the incidence of thyroid cancer appears to be much higher than that following the Chernobyl accident.
A comparison of the thyroidal consequences following the Fukushima and Chernobyl nuclear reactor accidents is discussed. We also summarize the recent increased incidence in thyroid cancer in the Fukushima area following the accident in relation to increased thyroid ultrasound screening and the use of advanced ultrasound techniques.
bDepartment of Global Health, Medicine and Welfare, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Nagasaki Prefecture, Japan
Correspondence to Shigenobu Nagataki, MD, PhD, President, Radiation Effects Association, 1-9-16 Kajicho, Chiyodaku, Tokyo, 101-0044, Japan. Tel: +81 3 5296 1481; e-mail: Shigenobu.firstname.lastname@example.org
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