EFFECTIVE HALF-LIFE OF RADIOACTIVE IODINE IN THERAPEUTIC DOSES FOR HYPERTHYROIDISM (in Spanish)
Tests were conducted in 25 hyperthyroid patients, who had never received radioiodine or antithyroid drugs, to determine whether the thyroid half-life value (t/sub 1/3/) of an exploratory dose of I/sup 131/ could be used to calculate the required therapeutic dose. For an exploratory dose of 20 mu C of I/sup 131/the t/sub 1/2/ value varied from 1.8 to 8.8 days, with a mean of 4.6 days. Higher t/sub 1/2/ values were found for the therapeutic dose (4.6 to 10.8 days, mean 6.9 days) in 21 of the 25 cases. This t/sub 1/2// value approaches that of the euthyroid value (7.4 days). A possible explanation for this approach toward normal values is that the largest quantity of radiation is received during the first week, resulting in functional modification of the thyroid, although modification of the clinical picture usually shows up later. These results differ from those of several previous studies in which the therapeutic dose t/sub 1/2//was lower than that of the test dose. Calculation of the thyroid dose in rads gives a mean of 7.5 rad, and the therapeutic t/sub 1/2// value gives 11.4 rad. In an unpublished study of 25 other patients conducted with the purpose of evaluating the possible diagnostic use of the exploratory t/sub 1/2// a value of 3.72 days was obtained. Thus the calculated amount of radiation received by the gland will differ appreciably when the estimations are based on the exploratory as compared with the therapeutic t/sub 1/2//values. Furthermore, the test dose value provides only an approximation of the therapeutic dosage; other data are required for a more precise estimation. (BBB)
- Research Organization:
- Centro de Endocrinologia y Metabolismo, Facultad de Ciencias Medicas, Rosario, Argentina
- NSA Number:
- NSA-17-038671
- OSTI ID:
- 4634868
- Journal Information:
- Medicina (Buenos Aires) (Argentina), Vol. Vol: 22; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- Spanish
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