Radioactive Iodine 131I Treatment Research Articles

Influence of Short-Term Dietary and Therapeutic Iodine Restriction on the Therapeutic Effects of Radioactive Iodine Therapy in Patients with Graves' Disease.

Background: Several studies have investigated the factors affecting the effects of radioactive iodine (131I) treatment (RAIT) in patients with Graves' disease. However, the influence of dietary or therapeutic iodine on the effect of RAIT has not been fully elucidated yet. The aim of this study was to investigate whether dietary or therapeutic iodine before RAIT influences the therapeutic effects of RAIT with a fixed-dose regimen and a short-term restriction of iodine intake in an iodine-sufficient area. Materials and Methods: We retrospectively analyzed 81 Japanese patients with Graves' disease treated with the following RAIT regimen: dietary iodine restriction for 7 days as well as discontinuation of antithyroid drugs (ATDs), potassium iodine (KI), or both for 5 days before RAIT. On the day of RAIT, we measured urinary iodine content to estimate daily iodine intake. After RAIT, we adjusted the dose of ATDs, KI, or both according to serum thyroid hormone levels every 1-2 months. Using the data from these patients, we investigated the effect of dietary and therapeutic iodine on the therapeutic effects of RAIT. The therapeutic effects at 1 year after RAIT were evaluated based on the necessity of ATDs, KI, or both. Results: Dietary iodine intake was weakly correlated with 131I uptake (RAIU), but the dose of therapeutic iodine was not correlated with RAIU. The therapeutic effects of RAIT were strongly negatively associated with estimated thyroid volume before RAIT. Neither dietary iodine intake nor therapeutic iodine before RAIT affected this association. Conclusion: This study did not find an association between short-term dietary or therapeutic iodine restriction before RAIT and the therapeutic effects of RAIT in an iodine-sufficient area.

Predictive Factors of Outcomes in Personalized Radioactive Iodine (131I) Treatment for Graves’ Disease

BackgroundGraves’ disease (GD) is the most common cause of hyperthyroidism in iodine-sufficient areas. Radioactive iodine 131I treatment (RIT), as the 1st therapeutic option, is widely accepted by doctors and patients. The aim of this study was to investigate factors influencing the success rate of calculated RIT in GD. MethodsThyroid function outcome (hyperthyroidism or euthyroidism/hypothyroidism) was verified retrospectively at least 1 year after RIT and was compared with presenting clinical characteristics and pre-RIT parameters in 167 patients with GD treated with 131I-iodide in the authors’ institute. ResultsAfter RIT, 83 patients (49.7%) became euthyroid, 64 patients (38.3%) became hypothyroid and 20 (12.0%) remained hyperthyroid. Multiple logistic regression analyses demonstrated that there was no statistically significant association between RIT outcomes and sex, age, history of GD, previous antithyroid drug treatment, thyroid hormone levels, thyroid gland mass or radioactive iodine 131I dosage. The only variables associated with the success rate were the course of disease over 6 months (odds ratio, 3.70; confidence interval, 1.75–7.17; P=0.014) and 2-hour radioactive iodine uptake (RAIU) >58.5% (odds ratio, 4.08; confidence interval, 2.03–7.83; P=0.005). Conclusionsour study has shown that a calculated approach for the treatment of GD was effective, but high failure rates were observed in patients presenting higher 2-hour RAIU, particularly those with 2-hour RAIU of more than 58.5%.

Iodine-131 induced hepatotoxicity in previously healthy patients with Grave’s disease

ObjectiveTo describe the association of the rare and serious complication of liver toxicity in previously healthy Grave’s disease (GD) patients after the treatment with radioactive iodine 131I (RAI).Case presentationWe report the clinical, laboratory and pathologic findings of 2 cases of severe liver toxicity associated with the treatment with RAI in previously healthy patients with GD. Clinical examination and laboratory investigations excluded viral hepatitis, autoimmune hepatitis, granulomatous disease, primary biliary disease, extrahepatic biliary obstruction, and heart failure.Case 1: A previously healthy 52-years old man reportedly having a typical GD but following RAI treatment, concomitantly developed severe liver toxicity that required 1 week of treatment in hospital.Case 2: A previously healthy 34-years old woman is reported as having a typical GD but developed jaundice following RAI treatment that required several weeks of in hospital treatment in the hepato-biliary department.In both cases, the liver dysfunction resolved after intensive treatment with hepato-protective agents. In this report the therapeutic considerations as well as the pathogenetic possibilities are reviewed.ConclusionTo the best of our knowledge, this is the first description of the association observed, which is rare but may be severe and should be considered in any case of thyrotoxicosis where a liver dysfunction develops after the treatment with radioactive iodine 131I.