Radioiodine uptake

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

Greer MA, Goodman G, Pleus RC, Greer SE (2002) Health effects assessment for environmental perchlorate contamination the dose response for inhibition of thyroidal radioiodine uptake in humans. Environ Health Perspect 110 927-937... 

Medicinal or dietary iodine interferes with all in vivo tests of radioiodine uptake, producing low uptakes that may not reflect a true decrease in hormone synthesis. 

In most patients with hyperthyroidism, T3, T4, FT4, and FT3 are elevated and TSH is suppressed (Table 38-2). Radioiodine uptake is usually markedly elevated as well. Antithyroglobulin, thyroid peroxidase, and TSH-R Ab [stim] antibodies are usually present. 

Crocker DG. Nuclear reactor accidents—the use of KI as a blocking agent against radioiodine uptake in the thyroid—a review. Health Phys 1984 46(6) 1265-79. 

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... 

Radioiodine uptake can be used to test thyroid function, though technetium would be more usual. Scanning may be used for the identification of solitary nodules, and in the differential diagnosis of Graves disease from the less common thyroiditides (e.g. de Quervain s thyroiditis). In the latter, excessive thyroid hormone release caused by follicular cell damage can cause clinical and biochemical features of hyperthyroidism, but uptake is reduced. 

Gopal, R. et al.. Electroporation A novel approach to enhance the radioiodine uptake in a human thyroid cancer cell line, Appl. Radiat. 

Evans TC, Kretzschmar RM, Hodges RE, et al. 1967. Radioiodine uptake studies of the human fetal thyroid. J Nucl Med 8 157-165. 

Nine of the patients were shown to be hyperthyroid clinically, biochemically, and by radioiodine uptake, but not by biological half-life three patients were found to be hypothyroid by the same criteria. As with the euthyroid patients, none had received thyroid or antithyroid medication or extraneous iodine. 

Figure 56.4 The figure shows thyroid scintigraphy with and a perchiorate (KCiOd testing in a ohiid affected with TiOD due to TPO mutations. A high radioiodine uptake (12.63%, normai vai-ues 1 -5) is observed at the seoond hour, and a totai discharge 1 h after the administration of 400 mg of KCi04 is aiso documented.

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. 

Depletion of plasma iodide by following a diet with restricted iodine content is a complementary approach to the stimulation of thyroid tissue by endogenous or rTSH. Iodine depletion is thought to enhance radioiodine uptake and retention by thyroid tissue, by both increased expression of the sodium iodide symporter within thyroid cells (De La Vieja et al., 2000), and by reduced competition for uptake due to a reduced plasma iodide concentration. 

Morris et al. (2001) retrospectively reviewed the ablation rates following initial radioiodine treatment postthyroidectomy for differentiated thyroid cancer patients in a single institution in the US. In this center a written comprehensive low-iodine diet was introduced in 1996 to replace a policy of limited simple verbal advice to avoid iodized foods, enabling a retrospective comparison between two different cohorts. Successful ablation was deemed to have occurred if there was no radioiodine uptake in the area of the thyroid bed on a diagnostic uptake scan performed between 4 and 42 months post-ablation. The was no statistically significant difference in ablation rates between 50 patients treated prior to 1996 who received minimal dietary advice with a 62% successful ablation rate, and with 44 patients post-1996 who received the... 

Using Retinoids to Increase Radioiodine Uptake in Thyroid Cancer Role as Potential Redifferentiation Agents... 

Using Retinoids to increase Radioiodine Uptake in Thyroid Cancer 993... 

On the basis of the apparent redifferentiation in thyroid cancer cell lines by RA, there is significant interest in assessing the efficacy of RA in restoring radioiodine uptake in patients with recurrent or metastatic thyroid cancer. 

Table 102.1 Summary of data from clinical studies investigating the effect of retinoids on radioiodine uptake... 

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