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Related to iodine-131: thallium-201


A radioisotope of iodine that emits beta and gamma rays, has a half-life of 8.05 days, and is used as a tracer in thyroid studies and as therapy in hyperthyroidism and thyroid cancer.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


(i'o-din?, -den?) [Gr. ioeides, violet-colored + -ine] I
A nonmetallic chemical element of the halogen group, atomic weight (mass) 126.904, atomic number 53, specific gravity (solid, 20°C) 4.93. It is a black crystalline substance with a melting point of 113.5°C; it boils at 184.4°C, giving off a characteristic violet vapor. Sources of iodine include vegetables, esp. those growing near the seacoast; iodized salt; and seafoods, esp. liver of halibut and cod, or fish liver oils.
CAS # 7553-56-2


Iodine is part of the hormones triiodothyronine (T3) and thyroxine (T4), and prevents goiter by enabling the thyroid gland to function normally. The amount of iodine in the entire body averages 50 mg, of which 10 to 15 mg is found in the thyroid. The adult daily requirement for iodine is from 100 to 150 µg. Growing children, adolescents, pregnant women, and those under emotional strain need more than this amount of iodine.

Deficiency Symptoms

Iodine deficiency in the diet may lead to simple goiter characterized by thyroid enlargement and hypothyroidism. In young children, this deficiency may result in retardation of physical, sexual, and mental development, a condition called cretinism.


131I See: radioactive iodine

protein-bound iodine

Abbreviation: PBI
Iodine that is attached to serum protein. In the past, thyroid function was tested with a serum measurement of PBI.

radioactive iodine

Any of the radioactive isotopes of iodine, esp. iodine-131, used in diagnosis and treatment of thyroid disorders and in the treatment of toxic goiter and thyroid carcinoma.
See: radioiodine

tincture of iodine

See: tincture
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References in periodicals archive ?
Sun's comments about the relationship between iodine-131 ([sup.131]I), hypothyroidism, and simple diffuse goiter suggest a misunderstanding of our study findings.
Atkins, "Side effects of "rational dose" iodine-131 therapy for metastatic well-differentiated thyroid carcinoma," Journal of Nuclear Medicine, vol.
The rate of decay of iodine-131 at time t is directly proportional to the quantity of iodine-131, I(u), present at time t: dI(t)/dt = -k x I(t), where k > 0.
From 1944 to 1957 a total of 724,779 curies of iodine-131 were released into the atmosphere.
The DNA in your thyroid cells is a major target of beta radiation from iodine-131. (16), (17) As it breaks and is repaired, abnormal DNA sequences can arise, producing mutations that lead to cancer.
"A person would have to drink some 96,000 litres of milk with We iodine-131 at the current levels to exceed the annual safe limit set to protect consumers."
Elevated levels of iodine-131, a radioactive substance that decays quickly, were another sign that radiation is leaking from the plant.
"Exposure to radionuclides, such as iodine-131 and cesium-137, increases the incidence of cancer.
The amount of iodine-131 found south of the plant does not pose an immediate threat to human health but was a "concern", said the Nuclear and Industrial Safety Agency.
The Health Protection Agency said that trace levels of the radioactive chemical iodine-131 had been detected by measurements taken at a monitoring station in Oxfordshire.
The Atomic Energy Council stated that airborne radioactive iodine-131 was detected in both northern and southern parts of the island but it was well below the safe limit.