Thyroid gland radioiodine

Primary hypothyroidism is characterized by a decrease in T4 and an increase in TSH levels. Primary hypothyroidism is caused by acute or chronic inflammation of the thyroid gland, radioiodine therapy, excess intake of antithyroid drags, and surgery. 

The selective uptake of iodide ion by the thyroid gland is the basis of radioiodine treatment in hyperthyroidism, mainly with although various other radioactive isotopes ate also used (40,41). With a half-life of eight days, the decay of this isotope produces high energy P-particles which cause selective destmction within a 2 mm sphere of their origin. The y-rays also emitted are not absorbed by the thyroid tissue and are employed for external scanning. 

Increased radioiodine uptake in the thyroid indicates increased hormone production by the thyroid gland. 

NCRP, Protection of the Thyroid Gland in the Event of Releases of Radioiodine, Report 55, National Council on Radiation Protection and Measurements, Bethesda, MD, 1977. 

The ability of KI to block the thyroidal uptake of I and its incorporation into Tg would prove useful in the event of an accident at a nuclear power plant. In such an event, large quantities of radionuclides, including isotopes of radioiodine, could be released into the atmosphere. Administration of KI Thyro-Block) to inhibit the uptake and incorporation of radioiodine would be the most effective means of limiting the potential damage to the thyroid gland. 

Different forms of radioiodine have been used at different times, including 123I, 12SI, and 131I. Radioactive iodine is used to scan the thyroid gland and in the treatment of thyrotoxicosis. See in the monograph on Radioactive iodine. 

Iodine - The importance of oxidation-state speciation of radioiodine was recognised at a very early stage because of its ability to accumulate in and cause damage to the human thyroid gland. Iodine-131 (t1/2 = 8.04 days) would therefore be... 

Astwood EB, Bissell A (1944) Effect of thiouracil on the iodine content of the thyroid gland. Endocrinol 34 282-296 Ching M (1981) Dose-related effect of growth hormone on thyroidal radioiodine uptake. Horn Res 14 234—42 Gutshall DM, Pilcher GD, Langley AE (1989) Mechanism of the serum thyroid hormone lowering effect of perfluoro-n-decanoic acid (PFDA) in rats. J Toxicol Environ Health 28 53-65... 

D. The uptake by the body of radioisotopes can be blocked in some cases. For example, potassium iodide or iodate if given prior to or soon after an intake of radioiodine, will reduce the uptake of radioiodine by the thyroid gland. Similarly, orally administered Prussian Blue will reduce the absorption of cesium from the gut and Alginate will reduce strontium absorption. No policy exists which would allow for NATO forces to stock and issue chelators. 

Hypothyroidism is common and is most often due to the destruction of the thyroid gland by autoimmune disease, surgery or radioiodine therapy. 

Hashimoto s and other thyroiditis causing hypothyroidism rarely cause goiter, as they are usually associated with atrophy of the thyroid gland. Nonetheless, goiters in these situations should be treated with thyroxine- replacement therapy. The replacement dose of thyroxine is lower in the elderly than in younger patients, and titration should also be slow in the elderly to avoid cardiac toxicity. Patients also require thyroxine therapy following surgical thyroidectomy or radioiodine ablation, to suppress serum TSH to below normal or undetectable levels to reduce the... 

Radloiodlne Treatment Radioiodine therapy is particularly well-suited for the treatment of autonomously functioning thyroid tissue. Radioactive iodine, like the natural element, is taken up by the thyroid gland via an active process (the sodium iodide symporter) and accumulates within the thyroid gland. The therapeutic effect occurs as a result of tissue destruction (radiation thyroiditis) caused by short-reached (3 radiation detection is enabled due to emission of a small portion of irradiation. The radioactive material is selectively trapped by the more active autonomously functioning cells and, to a lesser extent, by normal thyrocytes, which depend on TSH stimulation to increase iodine uptake. 

After iodization, there has been an increase in urinary iodine concentration, an increase in plasma inorganic iodine level and a decrease in thyroid iodine clearance and radioiodine uptake by the thyroid gland in normal subjects. 

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