O Emprego do Radioiodo no Estudo da Função Tireoidiana

Abstract

The development of the techniques of radioiodine application on the thyroid function has granted a general view of the iodine metabolism from the most rudimental vertebrated beings to man and from the embryo to the grown up animal. In the diagnostic of the thyroid dysfunctions the main determinated values are (generally 24 hs. after the dose): 1) iodide úptake 2) I¹³¹ excretion in the urine 3) iodide salivary excretion 4) conversion rate 5) PBI (plasma bound iodine). The two last processes study, specially, the organic phase of the iodine metabolism while the precedent estimate the inorganic phase. More precision and simplicity of the techniques concerned with radioiodine have displaced the diagnostic of the thyroid dysfunctions by the basal metabolismo (chiefly hyperthyroidism) and By the sérum cholesterol chiefly hypothyroidism). The determination of Chemical PBI, though fairly accurate, does not present the conditions of quick and simple measure as in the radioiodine test. We have introduced some small changes in COOPER’S and Abbott Laboratory’s techniques for the determination of FBI, regarding mainly less adsorption to the tubes walls as well as better carrying in the protein precipitations. We have discussed the techniques of the scintigram’s determination, of measurements of the gland’s mass, of scintigrams interpretation pointing out the greater incidence of cancer in the solitary and cold nodules as well as the localization of thyroid cancer metastasis. Finally, we present a study concerning the doses used in our tests and the irradiation of the pacients in wich we verify that the pacient’s irradiation in the radioiodine tests is same level with that of a series of radiographies of the gastrointestinal system.