radioactive iodine

radioactive iodine

n.

Any of the radioisotopes of iodine, especially I¹³¹, I¹²⁵, or I¹²³, used as tracers in biology and medicine.

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radioactive iodine (RAI),

a radioactive isotope of iodine used in diagnostic radiology and radiotherapy, especially in the treatment of some thyroid conditions. A common form is ¹³¹I. Also called radioiodine.

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iodine

a chemical element, atomic number 53, atomic weight 126.904, symbol I. See Table 6. Iodine is essential in nutrition, being especially prevalent in the colloid of the thyroid gland. It is used in the treatment of hypothyroidism and as a topical antiseptic. Iodine is a frequent cause of poisoning. See also iodism.

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iodine-125

a radioisotope of iodine having a half-life of 60 days and a principal gamma-ray photon energy of 28 keV; used as a label in radioimmunoassays and other in vitro tests, and also for thyroid imaging. Symbol ¹²⁵I.

¹²³iodine-metaiodobenzylguanidine

a radioisotope which concentrates in chromaffin cells; used in diagnostic scintigraphy, e.g. in cases of pheochromocytoma.

iodine-131

a radioisotope of iodine having a half-life of 8.1 days and a principal gamma-ray photon energy of 364 keV; used in treatment of hyperthyroidism and carcinoma of the thyroid, in thyroid function testing, and in imaging of the thyroid gland and other organs. Symbol ¹³¹I.

iodine deficiency

may occur in all species under certain conditions; in dogs and cats, a factor in all-meat diets. See also goiter.

iodine contrast agents

iodine salts are opaque to x-rays; therefore they can be combined with other compounds and used as contrast media in diagnostic x-ray examinations.

iodine nutritional deficiency

is characterized by goiter, neonatal mortality and alopecia.

iodine poisoning

occurs usually due to accidental overdosing. It causes lacrimation, anorexia, coughing due to bronchopneumonia, and a heavy dandruff. Paradoxically, iodine excess may result in thyroid hyperplasia and goiter, especially in the young.

protein-bound iodine

a test of thyroid function. See also protein-bound iodine (PBI) test.

radioactive iodine

see iodine-125, iodine-131 (above).

iodine residues in milk

careless use of iodine-based teat dips results in unacceptable residues of iodine in milk.

iodine solution

contains 2% free iodine and 2.4% sodium iodide in an aqueous solution.

iodine solution (strong)

contains 5% free iodine and 10% potassium iodide in an aqueous solution.

tamed iodine

see iodophor.

iodine trapping

the selective absorption of iodine from the circulation by the thyroid gland.

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radioactive iodine

Radioiodine A radioisotope of iodine–eg, 131I or 123I, used for imaging or to treat CA. See Radioactive iodine uptake.