*27 children developed thyroid cancer!
*Prof.Hayano said "No children were exposed to internal radiation"
福島の住民内部被曝、15歳以下ゼロ 12年５月以降 11/4/2013 Nikkei Shimbun
Professor Hayano of Tokyo University has been in charge of measuring the amount of internal exposure to ionizing radiation for residents of Fukushima Ibaragi prefecture, using Wholebody counter at Hirata central hospital in Hirata village, Fukushima prefecture. He measured 33,000 residents between October, 2011 and November, 2012. He announced that he had only found cesium137 in 1% of the residents since last March. He had measured 10,000 children under 15 years old since last May, but he didn't detect any C137 in all of them. He concluded that the reasons for decreasing no. of the residents who have been exposed to cesum137 is well established measuring food system and the residents being much more careful not to eat radioactively contaminated food.
11年11月と同12月は15％から放射性セシウム137が検出された。12年３月、衣服の汚れなどの影響を取り除くため、検査着に着替え て体内被曝量を測る方法に変更した後は平均で１％程度になった。 15歳以下に限ると、12年３～４月に計12人から検出されたが、５月以降は１人も検出さ れなかった。
Mr. Aoki 青木fukurounokai@gmail.com
ご 質問の件ですが、300Bq/Bodyはご指摘のように高すぎると考えています。 ただ、いろいろな自治体で自主的にWBCを導入して測定しているところでも、検出限界はセシウム137,134それぞれ250Bq/Body程度です。 250から300程度が現在のWBCの「検出限界」の限界のようです。 測定時間を長くすれば、時間のルート（平方根）倍で検出限界は下がります。 尿検査はWBCと比べ数倍から数十倍検出限界が低い。 （感度が高い）ということです。
Detection limit is 300Bq/kg for each C134 and C137 at Hirata Hospital which I think it's set up high. Normally it is between 250-300Bq/kg for each C134 and C137. I think 250-300Bq/kg is the best Wholebody counter can measure. Longer measurement can detect more cesium in the body if the background radiation is low. Normally the atmospheric dose is high in Fukushima prefecture. Therefore I recommend a urine test which is about 10 times more accurate than wholebody counter.
*Prof. Hayano and his team surveyed and published the report as follows:
Extensive whole-body-counter surveys carried out at the Hirata Central Hospital between October, 2011 and November, 2012, however show that the internal exposure levels of residents are much lower than estimated. In particular, the first sampling-bias-free assessment of the internal exposure of children in the town of Miharu, Fukushima, shows that the 137Cs body burdens of all children were below the detection limit of 300 Bq/body in the fall of 2012. These results are not conclusive for the prefecture as a whole, but are consistent with results obtained from other municipalities in the prefecture, and with prefectural data.
Miharu-machi can't be used as an example area because it was one of a few areas in Fukushima prefecture where Iodine tablets were distributed soon after the accident. Therefore naturally they should have been less affected by the fallout of the disaster comparing to residents in the other areas.