11 yr old exposed to 100 mSv after Fukushima explosion 福島11歳少女、事故後100mSv被ばく

　
東京新聞より：Tokyo newspaper

東京電力福島第一原発事故の直後、福島県双葉町にいた十一歳の少女が、喉にある甲状腺に推計で一〇〇ミリシーベルト程度の被ばくをしたと報告されていたことが、国の研究機関・放射線医学総合研究所（放医研）の文書から分かった。一〇〇ミリシーベルトは国などの資料で放射線の影響でがんの発症が増加し得る目安として使われてきた。しかし、国はこれまで「一〇〇ミリシーベルトの子どもは確認していない」と発表し、この報告は伏せられていた。　（榊原崇仁）
Immediately after the TEPCO Fukushima Daiichi Nuclear Power Plant accident, it was reported that an eleven-year-old girl in Futaba-cho, Fukushima Prefecture was exposed to an estimated 100 millisieverts of thyroid in the throat. It was found from the documents of the research institute and the Institute of Radiological Medicine (NIRS). One hundred millisieverts have been used in materials such as national data as a guideline for increasing the incidence of cancer due to the effects of radiation. However, the country has so far said, "We have not confirmed a child of 100 millisieverts," and the report was declined. (Takahito Sakakibara)

　文書は、事故から二カ月後、二〇一一年五月二日の放医研の「朝の対策本部会議メモ」。本紙の情報開示請求で公開された。それによると、会議では、十一歳の少女の実測値が「頸部（けいぶ）５－７万ｃｐｍ（ＧＭで測定）」と示され、「取り込みが３日前として、甲状腺等価線量で１００ｍＳｖ程度」と報告があった。
The document is the “Morning Countermeasures Headquarters Meeting Memorandum” by NIRS on May 2, 2011, two months after the accident. It was published in a request for information disclosure on this paper. According to the report, the actual measurement value of an 11-year-old girl was shown to be "neck (Keibu) 50,000-70,000 cpm (measured by GM)" at the meeting, and "the thyroid equivalent dose was 100 mSv when the intake was 3 days ago. Degree ”.

　甲状腺は首の部分にあり、放射性ヨウ素が集まりやすい。国や福島県の公表資料には「がんのリスクは一〇〇ミリシーベルト未満で検出困難」「チェルノブイリ事故では一〇〇ミリシーベルト以上でがん発症」と記されている。

The thyroid gland is located in neck, and radioactive iodine can easily be collected. A document released by the government and Fukushima Prefecture states that "the risk of cancer is less than 100 millisieverts, which is difficult to detect." "In the Chernobyl accident, cancer develops at over 100 millisieverts."

　メモや関連文書などによると、測定したのは県職員の放射線技師。県は事故直後から、避難者らの体についた放射性物質を調べ、除染する検査を実施しており、この技師は三月十三～十五日、派遣された同県郡山市の会場で、頭や衣服などの汚染を調べていた。検査機器として「ＧＭサーベイメータ」が使われた。甲状腺の放射性ヨウ素の測定は通常、体内からの放射線を調べやすい「ＮａＩサーベイメータ」を使うが、技師がいた検査会場にはなく、ＧＭで代用したとみられる。
According to memos and related documents, it was the radiologist of the prefecture staff who measured it. Immediately after the accident, the prefecture examined the radioactive substances on the evacuees' bodies and carried out an inspection to decontaminate them,  looking for contamination of my head and clothes. A "GM survey meter" was used as an inspection device. To measure radioactive iodine in the thyroid, a "NaI survey meter", which is easy to check radiation from inside the body, is usually used.

　記録も混乱の中で書き残されなかったが、結果は一一年四月、検査応援のために福島滞在中の徳島大の誉田（ほんだ）栄一教授と佐瀬卓也講師（現・核融合科学研究所准教授）に伝えられたという。
The record was not left unrecorded due to the confusion, but the result was reporeted to Professor Eiichi Honda of the University of Tokushima and the current Associate Professor of Nuclear Fusion Science Institute, Takuya Sase who were staying in Fukushima to support the examinations in April 2011.

　佐瀬氏はサーベイメータで示された汚染の程度から、少女の甲状腺に取り込まれた放射線ヨウ素を「十数キロベクレル相当」と試算し、現地にいた放医研職員に連絡。この試算を基に、会議で「一〇〇ミリシーベルト」が報告されたとみられる。徳島大の二人によると、技師は「少女は爆発があった時、『（原発がある）双葉町にいて友だちと外で遊んでいた』と話していた」という。
Dr. Sase estimated radiation iodine taken into the thyroid gland of the girl as "a dozen kilobecquerels" based on the degree of contamination indicated by the survey meter, and contacted the local NIRS staff. Based on this estimate, it is believed that "100 millisieverts" was reported at the meeting. According to Tokushima University, the engineer said, "When the explosion occurred, the girl said," I was in Futaba (where the nuclear power plant was) playing with friends. "

　政府の原子力災害現地対策本部は一一年三月下旬、ＮａＩを用いて十五歳以下の子どもの被ばく線量を測定し、すべて一〇〇ミリシーベルトの基準を下回ったと発表した。しかし、対象は避難や屋内退避が指示されなかった原発の三十キロ圏外の地域で、調べたのも千八十人のみ。事故当時、双葉町の少女らは、この測定から漏れた可能性が高い。
In late March 2011, the government's Nuclear Emergency Response Headquarters announced that it measured the exposure dose of children under the age of fifteen using NaI, and that it all fell below the standard of 100 millisieverts. However, the target was an area outside the nuclear power plant's thirty kilometers area where evacuation and evacuation were not instructed, and only 1,880 people were examined. At the time of the accident, the girls in Futaba are likely to have missed this measurement.

　放医研はこの値について「対策会議で出た情報を基にその場で簡易的に算出したもの。精密に検討しておらず、公表していない」とコメントしている。
The NIRS commented that this value was "calculated on the spot based on the information provided at the countermeasures meeting. It has not been examined precisely and has not been published."

＜放射線医学総合研究所＞　第五福竜丸事件を受けて１９５７年に設立。国の指針類では福島第一原発事故当時、「緊急被ばく医療体制の中心的機関」と位置付けられ、詳細な線量評価を担うほか、関係機関に対する助言や高度専門的な治療を行うと記されていた。所在地は千葉市稲毛区。
<NIRS> Established in 1957 following the 5th Lucky Dragon H-bomb incident. At the time of the Fukushima Daiichi Nuclear Power Plant accident, the national guidelines placed it as the "central institution of the medical system for emergency radiation exposure," which is responsible for detailed dose evaluations, as well as providing advice to relevant institutions and highly specialized treatment. The location is Inage-ku, Chiba.