Fukushima Daiichi nuclear power plant accident and the project of prefectural health management survey

The Project in the title after the Accident (Mar. 11, 2011) formally started in September in Fukushima Medical University in contract with the Prefecture on the national fund, of which progress and future aspect are reported. Based on a preliminary study in June, the subsequent fundamental investigation was conducted on all prefectural residents from August with questionnaire to see individual's health state and to estimate their accumulated maximal dose (mSv/4 months after the Accident). The preliminary study above was conducted for 29 thousands residents having been supposedly exposed to high dose at regions of Yamakiya, Namie and Iitate, 15 thousands (52%) of whom replied, where 99.3% were exposed to <10 mSv with the maximum of 23.0 mSv. In the fundamental study, until the end of May, 2012, 440 thousands replies (22%) were obtained from 2.05 million postal questionnaire mails sent, whose analysis was not finished, yet the results were retuned to individuals in due order of analysis completion. Another detailed investigation started almost simultaneously, which contained examinations of ultrasonic (US) thyroid testing for residents younger than age 18 y, of detailed health and mental state/life habit of 21 thousands people in the evacuation area, and of expectant/nursing mothers. Preliminarily, the internal exposure dose rate of thyroid was found to be 0.1 mcSv/h in one subject and <0.04 in 99% of 1,080 children in the Prefecture (Mar. 24-30), and US test of 38 thousands in the evacuation area revealed 0.5% of children were necessary for secondary examination due to benign lesions in the organ. To expectant/nursing mothers, questionnaire was performed asking about the health state during pregnancy, childbirth, mental health, etc. Reply was obtained in 55% within 2011 and follow-up has been conducted when judged to be necessary. Tasks derived from all matters described above include various things, of which continued long term follow-up supports are necessary. (T.T.)