This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints, Permissions and Rights Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Alexander, E. K. Articles by Larsen, P. R. Search for Related Content PubMed PubMed Citation Articles by Alexander, E. K. Articles by Larsen, P. R.

High Dose ¹³¹I Therapy for the Treatment of Hyperthyroidism Caused by Graves’ Disease

Thyroid Division, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115

Address all correspondence and requests for reprints to: P. Reed Larsen, M.D., Thyroid Division, Brigham and Women’s Hospital, H. I. M. Building, 77 Avenue Louis Pasteur, Room 560, Boston, Massachusetts 02115. E-mail: . plarsen{at}partners.org

Abstract

Radioactive iodine (¹³¹I) has become the most widely used therapy for patients with hyperthyroidism caused by Graves’ disease in the United States. There remains, however, significant variability among ¹³¹I dosing regimens, and it is clear that most patients ultimately develop hypothyroidism after therapy. To avoid persistent hyperthyroidism, we adopted a high dose ¹³¹I therapy protocol based on measurement of 24-h thyroid ¹²³I uptake designed to deliver 8 mCi (296 MBq) to the thyroid gland 24 h after ¹³¹I administration. To evaluate the efficacy of this protocol, we reviewed our clinical experience over a 7-yr period.

We treated 261 patients (219 women and 42 men) with hyperthyroidism caused by Graves’ disease with ¹³¹I [mean dose, 14.6 mCi (540 MBq)] between 1993 and 1999. Before treatment, 207 (79%) had received an antithyroid drug (109 propylthiouracil and 98 methimazole). We determined their thyroid status 1 yr after treatment in relation to age, pretreatment with an antithyroid drug, pretreatment thyroid size, and dose of ¹³¹I retained in the thyroid 24 h after treatment.

Among the 261 patients, 225 (86%) were euthyroid or hypothyroid 1 yr after treatment, and 36 patients (14%) had persistent hyperthyroidism and required a second treatment. The patients who had persistent hyperthyroidism were younger (P < 0.01), had larger thyroid glands (P < 0.01), higher pretreatment thyroid ¹²³I uptake values (P < 0.01), and higher serum T₄ concentrations (P < 0.01) and were more likely to have taken antithyroid medication before administration of ¹³¹I (P = 0.01). Five of these patients developed transient hypothyroidism, followed by thyrotoxicosis. There was an asymptotic, inverse relationship between the retained dose of ¹³¹I at 24 h and persistent hyperthyroidism, revealing a 5–10% failure rate despite delivery of up to 400 µCi (14.8 MBq)/g.

A dose of ¹³¹I that results in accumulation of 8 mCi (296 MBq) in the thyroid gland 24 h after administration is an effective treatment for the majority of patients with Graves’ hyperthyroidism. Young patients with larger thyroid glands, higher serum T₄ concentrations, and higher 24-h thyroid ¹²³I uptake values, and those pretreated with antithyroid medication for greater than 4 months are at higher risk for treatment failure. A higher dose of ¹³¹I may be advisable in such patients.

This article has been cited by other articles:

				G. A. Brent Graves' Disease N. Engl. J. Med., June 12, 2008; 358(24): 2594 - 2605. [Full Text] [PDF]

				J. C. Sisson, M. J. Schipper, C. C. Nelson, J. E. Freitas, and B. R. Frueh Radioiodine Therapy and Graves' Ophthalmopathy J. Nucl. Med., June 1, 2008; 49(6): 923 - 930. [Abstract] [Full Text] [PDF]

				M. A Walter, M. Briel, M. Christ-Crain, S. J Bonnema, J. Connell, D. S Cooper, H. C Bucher, J. Muller-Brand, and B. Muller Effects of antithyroid drugs on radioiodine treatment: systematic review and meta-analysis of randomised controlled trials BMJ, March 10, 2007; 334(7592): 514 - 514. [Abstract] [Full Text] [PDF]

				A. Iagaru and I. R. McDougall Treatment of Thyrotoxicosis J. Nucl. Med., March 1, 2007; 48(3): 379 - 389. [Abstract] [Full Text] [PDF]

				S. J. Bonnema, F. N. Bennedbaek, A. Veje, J. Marving, and L. Hegedus Continuous Methimazole Therapy and Its Effect on the Cure Rate of Hyperthyroidism Using Radioactive Iodine: An Evaluation by a Randomized Trial J. Clin. Endocrinol. Metab., August 1, 2006; 91(8): 2946 - 2951. [Abstract] [Full Text] [PDF]

				B. E Jensen, S. J Bonnema, and L. Hegedus Glucocorticoids do not influence the effect of radioiodine therapy in Graves' disease Eur. J. Endocrinol., July 1, 2005; 153(1): 15 - 21. [Abstract] [Full Text] [PDF]

				S. J. Bonnema, F. N. Bennedbaek, A. Veje, J. Marving, and L. Hegedus Propylthiouracil before 131I Therapy of Hyperthyroid Diseases: Effect on Cure Rate Evaluated by a Randomized Clinical Trial J. Clin. Endocrinol. Metab., September 1, 2004; 89(9): 4439 - 4444. [Abstract] [Full Text] [PDF]

				G Birrell and T Cheetham Juvenile thyrotoxicosis; can we do better? Arch. Dis. Child., August 1, 2004; 89(8): 745 - 750. [Abstract] [Full Text] [PDF]

				J. Horacek and J. A. Franklyn Radioiodine Treatment of Graves' Hyperthyroidism J. Clin. Endocrinol. Metab., December 1, 2003; 88(12): 6113 - 6113. [Full Text] [PDF]