One institutions' experience with a true standard 15 mCi dose of I-131 for the treatment of Graves' disease

Introduction: Currently, there is a lack of consensus on the fixed dosage of RAI to be administered for this purpose between the main guideline frameworks set forth by the American Thyroid Association (ATA), Society of Nuclear Medicine and Molecular Imaging (SNMMI), European Association of Nuclear Medicine (EANM) and the European Thyroid Association (ETA). In this retrospective study, we will investigate the effectiveness of using a standard dose of 15 mCi ±10% of RAI in the treatment of Graves'.

Methods: A retrospective chart review was conducted for the period between 1 May 2014 and 2 September 2020, to identify patients diagnosed with hyperthyroidism due to Graves' disease. The patients were grouped based on outcome and assessed for the efficacy of the dosage of 15 mCi ±10% of RAI in a successful treatment.

Results: Sixty-seven patients were identified that met the inclusion criteria between 1 May 2014 and 2 September 2020. Of the 67 RAI ablations; 60 patients became hypothyroid [60/67, (89.55%)], 2 euthyroid [2/67, (2.99%)] and 5 remained hyperthyroid [5/67, (7.46%)].

Conclusions: For the treatment of Graves' disease, the use of a standard low dose of 15 mCi ±10% has a high success rate without additional measurements or calculations beyond a standard planar image and 24-h uptake %. The adoption of a standard low dose of 15 mCi of I-131 across institutional guidelines would streamline dosage questions and eliminate the need to determine the weight of the thyroid for calculations in all RAI treatments for hyperthyroidism caused by Graves' disease.