“Do not take the stable iodine agent at present !”To inhabitants, particularly those with children
The protection of the thyroid gland with the stable iodine agent is unnecessary under thepresent conditions (as of 2011/3/20) for those who have already evacuated to refuge area(>20 km from the Fukushima Nuclear Power Plant) on/before March 19th.
All of you living in the area, where radiation exposure is concerned about, must be worried
about health problem possibly caused by the radioactive materials from the Fukushima
Nuclear Power Plant accident. Especially, parents with children must have a big concern
about radioactive-iodine exposure to children, and think about the administration of sable
iodine agent for the protection of thyroid gland.
A press release from The Ministry of Economy, Trade and Industry said that Nuclear Power
Plant Disaster Task Force instructed the administration of stable iodine agent at the time ofrefuge from the warning area (<20 km from the Fukushima Nuclear Power Plant). However,this message does not intend toward peoples who have already evacuated to the refugearea (>20 km from the Fukushima Nuclear Power Plant) on/before March 19th. From thescientific point of view, protection of the thyroid gland with the stable iodine agent is
unnecessary for those peoples, and rather it might be toxic in some case. Please do notgive the stable iodine agent by your own decision.
However, administration of the stable iodine agent might become necessary, in case ofdifferent situation.

Please keep watching the announcements from the Japanese

government, local governments, Tokyo Electric Power Company (TEPCO) and broadcast
news, and then follow the instructions from them.
1. Thyroid gland takes iodine, and synthesizes thyroid hormones. We, human being, takeiodine from food. If food contains enough iodine, the thyroid gland takes it and contains fullamount of iodine. On the contrary, if there is little iodine in food, the thyroid gland becomes
iodine-deficient state and efficiency of absorption of iodine goes up. Normal iodine does
not have radioactivity. However, there are radioactive iodine isotopes (such as I-131) and it
may adversely affect thyroid gland functions when excess amount is ingested. This might
be your concern.
2. Increased number of childhood thyroid cancer was seen after an accident in Chernobyl inthe Eastern European countries. It is reported that the main cause was due to internalradiation exposure from the radioactive iodine in milk. In the Chernobyl accident, Poland
surely distributed a stable iodine agent once to 90% of all Polish infants, four days afterlarge-scale radiation exposure outbreak.

Eventually, the number of childhood thyroid

cancer cases was not increased in Poland, whereas it increased in Ukraine and Belarus,
neighboring countries, which did not do so. However, this could not be considered as aresult of the stable iodine agent, but (1) Ukraine and Belarus are inland countries with little
iodine in food and soil, (2) In Poland facing to the sea, iodine-rich meal is taken, and (3)Poland prohibited the feeding by domestic milk after the accident, but fed by imported drymilk. These factors worked together well, and, as a result, there was not any increase ofthyroid cancer case in Poland.
3. In Japan, peoples take enough iodine in the normal eating habits, because soil in Japan
contains a lot of iodine. Thus, our thyroid gland is filled with stable iodine. It is unlikely thatconsiderable amount of radioactive iodine is absorbed in the thyroid and influences ourhealth.

Therefore, it is not necessary to take a stable iodine agent. It is dangerous to takecommercial gargle or disinfectant containing iodine.

Even more in baby, there is a risk tocause growth deterioration.
4. At present, there is no immediate risk of meal with radioactive iodine. When a large
amount of radioactive iodine spreads out in the soil, plants concentrate it in themselves,then cows eat plants, and radioactive iodine is concentrated more in the cows’ bodies.
After that, concentration of radioactive iodine in milk and other food rises. The thyroid glandis exposed to radiation, when people eat them.
5. Administration of stable iodine agent is strictly limited to (1) peoples who are assumed tohave high contamination of radioactive iodine, and (2) only once.

Preventive

administration of the stable iodine agent without exposure to high-level radioiodine, might
ever cause malfunction of thyroid gland, and induce efficient absorption of radioactive iodine
after a certain period of time.
6. It is reported that incidence of infant thyroid cancer does not increase under the thyroidal
radiation dose of 0.020 Gy (ICRP Pub94) (the thyroidal radiation dose in Ukraine andBelarus after Chernobyl accident was reported to be around 0.15-3.10 Gy).

This safety

dose threshold of 0.020 Gy is equivalent to 3 microCi of radioactive iodine in the body.

Itcorresponds to approximately 7,000,000 cpm (counts per minute) in thyroid gland by aradiation survey meter.
7. The Japanese Government has announced that some people with radioactivecontamination were detected through screening, who were then decontaminated and weregiven appropriate instructions.

In addition, the result of screening for the radioactivecontamination indicated that no peoples living in >20km from Fukushima Nuclear Power
Plant had contamination. Thus, it is thought that there is no internal contamination, whichmight adversely affect thyroid gland function. Appropriate instruction will be given by any
chance if contamination is recognized on the occasion of screening.
8. It was reported that the concentration of radioactive iodine in waterworks in Fukushima
City slightly increased on March 17, but this value was lower than the regulation limit, andthere is no health problem by drinking.
9. The risk of the thyroid cancer by radioactive iodine is only high for those under 40 years
old, especially in infants, but quite low in the older.
The serious situation continues, and, please follow governmental and related local
governmental announcement carefully. Thank you in advance.
The Japanese Society of Nuclear Medicine
National Institute of Radiological Sciences(2011/3/17)(2011/3/18 revision)
The second (2011/3/18 revision article)
The third (2011/3/20 revised and translated to English)