[Risk of thyroid cancer occurrence by nuclear disasters and its countermeasures]

Looking back at the Great East Japan Earthquake on March 11, 2011, besides further studying the appropriateness of the initial response and post-countermeasures against the severe Fukushima nuclear accident, the importance of the epidemiological study in human health risk management and the comprehensive radiation protection standard need to be emphasized; lessons learnt from the Chernobyl accident should be also implemented. Therefore, since May 2011, Fukushima Prefecture has started the "Health Care Project (Fukushima Health Management Survey Project)" for the purpose of long-term health care administration and medical diagnosis/treatment for the prefectural residents. In this issue, risk and countermeasures of thyroid cancer occurrence by nuclear disasters, especially due to radioactive iodine will be discussed despite the difficult challenge of accurate estimation of low dose and low-dose rate radiation exposures.