Dr. Tsubokura's Radiation Lecture Vol.123

Author: Masaharu Tsubokura M.D., PhD.

Editors: Akihiko Ozaki M.D., PhD., Yuki Senoo

245 Stable (non-radioactive) iodine tablets stored by municipalities

September 22, 2019

　　　　The 2011 Fukushima Daiichi nuclear accident provided a clear visual of the importance of an emergency response plan for a nuclear accident. Reflecting on the events that occurred during and after the nuclear accident, various countermeasures and preparations have been modified.

　　　　For example, one of the organizational preparations against nuclear accidents is the storage and distribution of “stable (non-radioactive) iodine” tablets.

　　　　Immediately after nuclear power plant accidents, there is a risk of thyroid gland exposure to radiation emitted from radioactive iodine released into the air, water, and food from the nuclear power plant. It is true that the risk of radiation exposure from radioactive iodine is only present in the early stage of the nuclear disaster since radioactive iodine has a short half-life of only eight days. However, radioactive iodine released from the power plant following the Chernobyl accident caused severe health consequences because it increased the incidence of thyroid cancer.

　In this context, stable iodine tablets are designed to prevent radiation exposure of the thyroid gland to radioactive iodine by filling the thyroid gland with a large amount of non-radioactive iodine before the radioactive iodine enters the body. To effectively prevent radiation exposure of thyroid glands, it is recommended to take stable iodine tablets at least 24 hours before exposure to radioactive iodine and at least 8 hours after exposure.

　　　　Currently, stable iodine tablets are distributed to every resident living in the areas within a 5-km radius of the power plant in advance. On the other hand, for the residents living in the areas within a radius of 5 to 30 km from the power plants, the local government is obliged to stock enough stable iodine tablets in public facilities and distribute them in case of a nuclear emergency.

246 Safe use of stable iodine tablets

September 29, 2019

The 2011 Fukushima Daiichi nuclear accident provided a clear visual of the importance of an emergency response plan for a nuclear accident. Reflecting on the events that occurred during and after the nuclear accident, various countermeasures and preparations have been modified.

As mentioned in the previous article, the storage and distribution of "stable (non-radioactive) iodine" tablets are part of the organizational preparations for a nuclear emergency. Stable iodine tablets are designed to prevent radiation exposure of the thyroid gland by occupying the thyroid gland with a large amount of non-radioactive iodine prior to the ingestion of radioactive iodine released from the nuclear power plant.　

　Most of the time, stable iodine tablets are given in the form of a small tablet. However, jelly or liquid forms have also recently become available for small children and infants.

　Some people may be worried about the side effects of stable iodine tablets on small children and infants. In fact, it has been shown that even when stable iodine tablets were distributed after the accident, some people did not give them to their children for various reasons.

　However, several previous studies have demonstrated the safety of stable iodine tablets in most populations. Furthermore, no severe side effects related to stable iodine tablets have been reported since the 2011 Fukushima nuclear disaster.

　However, stable iodine tablets do carry with them some precautions. First of all, new-born babies and pregnant women should not take stable iodine tablets repeatedly on a regular basis. Second, people with hypertension or an allergy to iodine should not take them either. Lastly, stable iodine tablets may aggregate the underlying health condition or induce strong allergic reactions in people with thyroid disease, pulmonary tuberculosis, renal failure, special dermatitis, or vasculitis. It is recommended to consult with medical doctors beforehand if you are concerned about taking the stable iodine tablets.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, 22nd and 29th September 2019 was reproduced for MRIC Global under the author's permission.