CONSULTING

Radiation Exposure and Health Effects
Fukushima Prefecture is continuing its health survey, which includes assessments of external and
internal doses and thyroid examinations. 299 In regard to the thyroid examination, the preliminary
survey—ultrasound wave examination for residents who were under 18 years old or younger and
lived in Fukushima Prefecture at the time of the accident—was conducted from October 2011 to
March 2014. As of the end of June 2015, 113 people were diagnosed with confirmed or suspected
thyroid cancer. 300 Of these, 99 people underwent surgery.
However, the Prefectural Oversight Committee Meeting for Fukushima Health Management Survey
concluded:
As a judgment based on a comprehensive assessment of the following facts, it is unlikely that the
thyroid cancers discovered until now were caused by the effects of radiation: the exposure doses were
generally smaller compared to those of the Chernobyl accident, the period from exposure to cancer
detection was short ranging from about one to four years, cancer was not found in those aged five
years old or younger at the time of the accident, and there was no significant difference in the regional
detection rates.
The first full-scale survey was conducted from April 2014 to March 2016, involving the subjects of
the preliminary survey and children who were born after the accident including those in utero at
the time of the accident. If nodules or cysts that are larger than a predetermined size are found in
the primary first examination, those people undergo a confirmatory examination.
Table 8: Confirmed or Suspected Thyroid Cancer Cases and Effective External Dose Estimates
Age at the time of the accident
Effective dose
[mSv]
0 - 5 6 - 10 11 - 15 16 - 18 Total
Male Female Male Female Male Female Male Female Male Female
Less than 1 0 0 3 0 1 4 2 0 6 4
Less than 2 0 0 0 1 3 4 3 3 6 8
Less than 5 0 0 1 0 0 2 1 1 2 3
Less than 10 0 0 0 0 0 0 0 0 0 0
Less than 20 0 0 0 0 0 0 0 0 0 0
20 and above 0 0 0 0 0 0 0 0 0 0
Total 0 0 4 1 4 10 6 4 14 15
Source: Prefectural Oversight Committee Meeting for Fukushima Health Management Survey, “Thyroid Ultrasound Examination
299 Fukushima Medical University, “Report of the Fukushima Health Management Survey (FY 2011-2013)”,
(revised version), 12 June 2015. see http://fmu-global.jp/?wpdmdl=1032, accessed 30 June 2016.
300 Prefectural Oversight Committee Meeting for Fukushima Health Management Survey, “Interim report on
the prefectural citizens health survey”, March 2016, (in Japanese), see
http://www.pref.fukushima.lg.jp/uploaded/attachment/158522.pdf, accessed 12 April 2016; and Shinichi
Suzuki et al., “Comprehensive Survey Results of Childhood Thyroid Ultrasound Examinations in Fukushima
in the First Four Years After the Fukushima Daiichi Nuclear Power Plant Accident”, THYROID, Volume 26,
Number 6, 2016, see http://online.liebertpub.com/doi/abs/10.1089/thy.2015.0564, accessed 10 June 2016.
Mycle Schneider, Antony Froggatt et al. 95 World Nuclear Industry Status Report 2016