AMERICAN THYROID ASSOCIATION?
Nuclear Radiation and the Thyroid
WHAT IS THE THYROID GLAND? WHAT IS THE PROOF THAT KI WORKS?
The thyroid gland is a butterfly-shaped endocrine gland After the 1986 Chernobyl nuclear accident, shifting winds
that is normally located in the lower front of the neck. blew a radioactive cloud over Europe. As many as 3,000
The thyroid's job is to make thyroid hormones, which are people exposed to that radiation developed thyroid cancer
secreted into the blood and then carried to every tissue in over the next 10 years. Most victims had been babies or
the body. Thyroid hormones help the body use energy, young children living in Ukraine, Belarus, or Russia at the
stay warm and keep the brain, heart, muscles, and other time of the accident. The region of excess risk extended
organs working as they should. up to a 200 mi radius from Chernobyl. Poland, immediately
WHY DOES THE THYROID GLAND NEED adjacent to Belarus and Ukraine, distributed KI to >95%
of their children within 3 days of the accident and did not
SPECIAL PROTECTION AFTER A RELEASE OF appear to have an increase in thyroid cancer during the
RADIOACTIVE MATERIAL? first 3 years of clinical follow up.
The thyroid gland needs iodine to produce hormones that WHO SHOULD TAKE KI?
regulate the body's energy and metabolism. The thyroid Since children are at the highest risk to exposure to
absorbs available iodine from the bloodstream. The radioactive iodine, KI should be available to all of them.
thyroid gland cannot distinguish between stable (regular) Because of the risk to the fetus, pregnant women should
iodine and radioactive iodine and will absorb whatever it also take KI in the event of a nuclear accident. Adults are
can. In babies and children, the thyroid gland is one of the at a lower risk but still may benefit from KI. In addition to KI,
most radiation-sensitive parts of the body. priority should be given to evacuation, sheltering (staying in
Most nuclear accidents release radioactive iodine into the an unventilated room with the doors and windows closed)
atmosphere, which can be absorbed into the body. When and avoiding contaminated food, milk, and water. KI should
thyroid cells absorb too much radioactive iodine, it can not take the place of any other protective measure.
cause thyroid cancer to develop several years after the
exposure. Babies and young children are at highest risk. WHEN SHOULD KI BE TAKEN?
The risk is much lower for people over 40. Thyroid cancer KI fills the thyroid cells with iodine and prevents the gland
seems to be the only cancer whose incidence rises after from absorbing radioactive iodine for approximately 24
a radioactive iodine release. Potassium iodide protects hours. People should take one dose a day while they are
only the thyroid, but it is the organ at greatest risk from being exposed to radioactive iodine until the risk no longer
radioactive iodine. exists. KI should be used only under instruction from local
WHAT IS POTASSIUM IODIDE (KI)? health authorities. Not every radioactive release includes
the radioactive iodine that can cause thyroid cancer.
Potassium iodide (KI) is the same form of iodine used Health authorities can determine which radioactive
to iodize table salt. Taking KI fills the thyroid with iodine, isotopes are released during a nuclear event. If radioactive
thus preventing radioactive iodine from being absorbed. iodine is released, then health authorities will advise on
If taken soon enough, KI protects the thyroid from when and how long to take KI.
radioactive iodine from all sources - milk, other foods,
air, and water. KI is a non-prescription drug that can be WHAT ARE THE RECOMMENDED KI DOSES?
purchased over the internet and at some pharmacies. KI is The FDA recommends the following doses:
available in pill and liquid forms. KI products approved by AGE______________________ DOSE
the Food and Drug Administration (FDA) are Iosat Tablets 0 - 1 months ........................ 15 mg
(130 mg), ThyroSafe Tablets (65 mg), and ThyroShield 1 months - 3 years .............. 32 mg
Solution (65 mg/ml). Properly packaged, Potassium iodide 3 - 12 years ......................... 65 mg
tablet's shelf life is at least 5 years and possibly as long as >12 years .......................... 130 mg
11 years. If you take a very old pill, it may not work fully but
it will not hurt you. A 15-mg dose can be given to a newborn 0-1 month
dissolving a 130-mg pill in 8 oz of a clear liquid
and feeding the newborn 1 oz of
1 This page and its contents
are Copyright ? 2018
the American Thyroid Association?
AMERICAN THYROID ASSOCIATION?
Nuclear Radiation and the Thyroid
WHO SHOULD NOT TAKE KI? WHY WASTE TIME TO TAKE A PILL IF YOU
Millions of people have taken KI but few serious side- ARE BEING TOLD TO EVACUATE?
effects have been reported. The only people who should Nuclear releases are unpredictable and traffic jams are
not take KI are those who have had a major allergic likely to delay speedy evacuation. People should take their
reaction to iodine; it is safe to take KI even if you have KI before they evacuate, following instructions from local
a shellfish or contrast dye allergy. During a nuclear health officials.
emergency, KI's benefit far outweighs any potential risk.
Adults over 40 years old do not need KI at all unless they WHY NOT PRE-DISTRIBUTE KI TO PEOPLE
are exposed to extremely high levels of radioactive iodine. 10 TO 50 MILES AWAY FROM A NUCLEAR
Patients with thyroid disease can safely take the pills in PLANT?
the FDA recommended doses. KI should be used for
10-14 days or as directed by public officials (until risk of The Department of Health and Human Services (HHS)
exposure has passed or other measures are implemented). has recommended distribution of KI to individuals residing
If KI is taken for a prolonged amount of time, it can lead to within 10 miles of a nuclear plant.
temporary hypothyroidism (underactive thyroid gland) or The American Thyroid Association (ATA) agrees with the
hyperthyroidism (an overactive gland) in some people. predistribution of KI to people living within 10 miles of a
Prolonged treatment can cause thyroid dysfunction nuclear plant and recommends stockpiling of KI for those
for very young children. Such children should be seen living within 50 miles of a nuclear plant. In areas beyond
afterward by a health professional. Patients with Graves' 10 miles and particularly beyond 50 miles of the nuclear
hyperthyroidism or with autonomous functioning thyroid facility, the most likely route of exposure will be through the
nodules should also be seen by their health care provider ingestion pathway.
IS THERE REASON TO BE CONCERNED ABOUT No one can predict how far a radioactive iodine cloud
might spread. After Chernobyl, higher than expected rates
THYROID CANCER? of thyroid cancer were found more than 200 miles away
In general, 90% of patients survive thyroid cancer. The from the nuclear plant. Thus, it is difficult to predict how
post-Chernobyl cancers have some aggressive features far from a nuclear plant the U.S. should distribute KI in
and have been unusual in affecting children younger than an effort to protect every person who might be exposed
10 years. Thyroid cancer survivors always remain at risk to radioactive iodine. Because of this uncertainty, the
for recurrence and require lifelong medical care. Likewise, American Thyroid Association recommends these levels of
the children who were exposed to radioactive iodine from coverage, determined by distance from the nuclear plant:
the Chernobyl accident, but have not developed thyroid DISTANCE ACTION
cancer, remain at risk for life and must continue to be ?0 - 10 mi Distribute KI in advance (``Pre-distribute'') to
tested though the question of surveillance is still unsettled. individual households, with extra stockpiles
stored at emergency reception centers
HOW SHOULD KI BE INCORPORATED INTO AN ?10 - 50 mi Stockpile KI in local public facilities such as
OVERALL EMERGENCY PLAN? schools, hospitals, clinics, post offices, and
KI is an adjunct to other critical responses. These are police and fire stations for distribution upon
evacuation or, if not recommended or not possible, notification by local health officials
sheltering (staying in an unventilated room with the doors WHAT ARE OTHER COUNTRIES DOING?
and windows closed), and avoiding contaminated food,
milk, and water. KI should not take the place of these and The World Health Organization endorses KI distribution.
any other protective measures. Many countries, including Belgium, Finland, France,
WILL TAKING KI PILLS LULL PEOPLE INTO A
Ireland, Japan, Sweden, and Switzerland, stockpile KI and
pre-distribute it in the areas adjacent to nuclear power
FALSE SENSE OF SECURITY? plants.
Not likely. Local authorities recommend that people leave
the vicinity of a nuclear emergency as quickly as possible.
People should be taught that KI is part of the response to
a nuclear accident in addition to evacuation. FURTHER INFORMATION
Further details on this and other thyroid-related topics are available in the patient thyroid
2 This page and its contents information section on the American Thyroid Association? website at www.thyroid.org.
are Copyright ? 2018 For information on thyroid patient support organizations, please visit the
the American Thyroid Association?
Patient Support Links section on the ATA website at www.thyroid.org
Should I take radiation protection pills? Types of anti-radiation pills. There are four primary anti-radiation pills recognized by the Centers for Disease Control (CDC). They are: Potassium Iodide (KI). KI is derived from stable iodine. Taking KI after exposure to high amounts of radioactive iodine can help shield the thyroid gland from damage due to radiation.
Title: Nuclear Radiation and the Thyroid
Subject: ATA Patient Education Web Brochures
Keywords: Nuclear Radiation
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