TREATMENT OF HYPERTHYROIDISM WITH RADIOACTIVE IODINE

https://doi.org/10.1016/S0889-8529(05)70307-8Get rights and content

Radioactive iodine (RAI) therapy for hyperthyroidism was first used in 1941 by physicians at Massachusetts General Hospital in Boston.7, 58 The first nuclide used was 130I, which has a half-life of 12.4 hours. In 1946, 131I became readily available from the Oak Ridge National Laboratory in Tennessee as a spin-off of atomic energy research conducted during World War II. The relatively low cost convenient half-life of 8 days and the effectiveness of treatment of hyperthyroidism with 131I rapidly led to its widespread adoption. It has become one of the standard therapies for hyperthyroidism and is now used throughout the world. Attempts have been made to use another isotope, 125I, for the treatment of hyperthyroidism in the hope of avoiding subsequent long-term hypothyroidism; however, it has no advantage over 131I. The properties of 123I that make it excellent for thyroid imaging—a short half-life, an appropriate gamma radiation emission energy, and a low radiation dose delivered to the thyroid gland—also make it ineffective for the ablation of thyroid tissue. Thus, only 131I is currently used for ablative thyroid therapy, both for hyperthyroidism and thyroid cancer.

Section snippets

Physiologic Considerations: Uptake of Radioactive Iodine

A prerequisite for RAI therapy is adequate thyroidal uptake of the isotope. Diseases appropriate for RAI treatment are Graves' disease, toxic autonomous nodules, and toxic multinodular goiters. Thyroid ablation is not indicated for central [thyrotropin (TSH)–dependent] hyperthyroidism and for patients with other causes of hyperthyroidism who have low RAI uptakes.

Conventionally, a 24-hour thyroid RAI uptake is measured using either 131I or 123I. However, shorter measurement times can be used,

PRETREATMENT WITH ANTITHYROID DRUGS BEFORE RADIOIODINE THERAPY

Opinions vary as to which patients need pretreatment before 131I administration. RAI therapy sometimes produces a radiation thyroiditis and follicular disruption, with release of stored thyroid hormone into the circulation.61, 70 Thyroiditis peaks between 10 and 14 days after dosing,10 resulting in an occasional patient who experiences worsening of hyperthyroid symptoms. There have been rare cases of thyroid storm occurring after RAI therapy.45 Accordingly, elderly patients and patients with

DOSE SELECTION

Despite more than 50 years' experience with RAI therapy, no unanimity exists regarding dose selection, although certain guidelines have become generally accepted. It is useful to consider the criteria for dose selection separately for Graves' hyperthyroidism and toxic nodular goiter. However, regardless of the manner in which the 131I dose is chosen, or which cause of hyperthyroidism is being treated, hypothyroidism can occur weeks, months, or years after RAI treatment. Each patient (or his or

RADIATION SAFETY CONSIDERATIONS AFTER TREATMENT WITH RADIOIODINE

In the United States, persons handling radioiodine must be licensed by the NRC. For many years, NRC rules have mandated that patients treated with more than 30 mCi (1.1 GBq) of 131I be hospitalized in a shielded room to minimize radiation exposure to others. Although no new scientific data have been reported, a more recent analysis by the NRC has determined that it is safe to release patients from hospital confinement after the administration of radioactive materials when the whole-body burden

PATIENT FOLLOW-UP AFTER RADIOIODINE THERAPY FOR HYPERTHYROIDISM

The optimal schedule for follow-up visits in the first 3 months after RAI therapy depends on the patient's overall condition and the 131I dosing philosophy. When the relatively high, size-based doses in Table 2 are used, the authors see patients for re-evaluation 6 and 12 weeks afterward if they are not taking ATD and 4, 8, and 12 weeks after therapy if patients are taking ATD or are otherwise fragile. Patients are asked whether they have noticed any change in thyrotoxic symptoms, in the amount

Carcinogenesis

The greatest concern regarding the use of RAI treatment for hyperthyroidism has been the possibility of carcinogenesis. After more than 50 years of using RAI for the diagnosis and treatment of hyperthyroid patients and despite many published series of cases and literature reviews, no clear consistent cause-and-effect relationship has been proved between medical radioiodine use and subsequent cancer.18, 28, 30, 36, 54 Extensive studies have shown no indication of an increase in subsequent

SUMMARY

Treatment of hyperthyroidism with RAI has been performed for more than a half century with efficacy and safety. For its optimal use, the physician must employ appropriate patient selection criteria and clinical judgment concerning pretreatment patient preparation. The dose of the 131I needed remains an area of uncertainty and debate; thus far, it has not been possible to resolve the trade-off between efficient definitive cure of hyperthyroidism and the high incidence of post-therapy

ACKNOWLEDGMENT

The authors thank Cheryl Culver-Schultz, Radiation Safety Officer of William Beaumont Hospital, Royal Oak, MI, for development of our radiation safety guidelines for patients.

References (78)

  • D.V. Becker et al.

    The results of radioiodine treatment of hyperthyroidism. A preliminary report of the Thyrotoxicosis Therapy Follow-up Study

  • G.E.B. Berg et al.

    Iodine-131 treatment of hyperthyroidism: Significance of effective half-life measurements

    J Nucl Med

    (1996)
  • A. Bockisch et al.

    Optimized dose planning of radioiodine therapy of benign thyroidal diseases

    J Nucl Med

    (1993)
  • H.B. Burch et al.

    Discontinuing antithyroid drug therapy before ablation with radioiodine in Graves' disease

    Ann Intern Med

    (1994)
  • H.B. Burch et al.

    Graves' ophthalmopathy: Current concepts regarding pathogenesis and management

    Endocr Rev

    (1993)
  • J. Clerc et al.

    Influence of dose selection on absorbed dose profiles in radioiodine treatment of diffuse toxic goiters in patients receiving or not receiving carbimazole

    J Nucl Med

    (1993)
  • D.S. Cooper

    Antithyroid drugs and radioiodine therapy: A grain of (iodized) salt

    Ann Intern Med

    (1994)
  • D.S. Cooper

    Treatment of thyrotoxicosis

  • L.J. DeGroot

    Radioiodine and the immune system

    Thyroid

    (1997)
  • L.J. DeGroot et al.

    Therapeutic controversies: Radiation and Graves' ophthalmopathy

    J Clin Endocrinol Metab

    (1995)
  • L.J. DeGroot et al.

    Graves' disease: Diagnosis and treatment

  • B.M. Dobyns et al.

    Malignant and benign neoplasms of the thyroid in patients treated for hyperthyroidism: A report of the Cooperative Thyrotoxicosis Therapy Follow-up Study

    Clin Endocrinol Metab

    (1974)
  • J.T. Dunn

    Choice of therapy in young adults with hyperthyroidism of Graves' disease

    Ann Intern Med

    (1984)

  • European Thyroid Association Committee on Radioiodine (131I) Therapy in Thyrotoxicosis: 131I therapy for Thyrotoxicosis: Towards 2000

    (1993)
  • T.C. Evans et al.

    Radioiodine uptake studies of the human fetal thyroid

    J Nucl Med

    (1967)
  • Food and Nutrition Board Committee on Dietary Allowances

    US National Research Council: Iodine

  • J.A. Franklyn

    The management of hyperthyroidism

    N Engl J Med

    (1994)
  • E. Gallegos et al.

    Graves' disease triggered by autoinfarction of an autonomously functioning thyroid adenoma

    J Nucl Med

    (1997)
  • M. Garcia et al.

    AACE clinical practice guidelines for the evaluation and treatment of hypothyroidism and hypothyroidism

    Endocr Pract

    (1995)
  • D. Glinoer et al.

    The management of hyperthyroid due to Graves' disease in Europe in 1986: Results of an international survey

    Acta Endocrinol

    (1987)
  • C.A. Gorman et al.

    Radiation dose in the selection of 131I or surgical treatment for toxic thyroid adenoma

    Ann Intern Med

    (1978)
  • G.D. Graham et al.

    Radioiodine treatment of Graves disease: An assessment of its potential risks

    Ann Intern Med

    (1985)
  • F. Hagen et al.

    Comparison of high and low dosage levels of 131-I in the treatment of thyrotoxicosis

    N Engl J Med

    (1967)
  • P. Hall et al.

    Late consequences of radioiodine for diagnosis and therapy in Sweden

    Thyroid

    (1997)
  • J.I. Hamburger et al.

    Diagnosis and management of large toxic multinodular goiters

    J Nucl Med

    (1985)
  • J.I. Hamburger

    Diuretic augmentation of 131I uptake in inoperable thyroid cancer

    N Engl J Med

    (1969)
  • L. Hegedüs et al.

    The determination of thyroid volume by ultrasound and its relationship to body weight, age, and sex in normal subjects

    J Clin Endocrinol Metab

    (1983)
  • J.V. Hennessey et al.

    Evaluation of early (5 to 6 hours) iodine 123 uptake for diagnosis and treatment planning in Graves' disease

    Arch Intern Med

    (1995)
  • R.E. Hodges et al.

    The accumulation of radioactive iodine by human fetal thyroids

    J Clin Endocrinol Metab

    (1955)

    • Cited by (65)

    • Non-Neoplastic Lesions of the Thyroid Gland

      2019, Head and Neck Pathology: A Volume in the Series: Foundations in Diagnostic Pathology

    • Treatment of adult Graves’ disease

      2018, Annales d'Endocrinologie
      Citation Excerpt :

      Even so, high-dose ablation (> 10–15 mCi) achieved success rates exceeding 80% [83,85]. With the dose-adjustment method, euthyroid status is rarely achieved and diminishes over follow-up, as incidence of post-radioiodine hypothyroidism increases year on year [86]. These results are probably due to calculation methods, which vary between studies and, if they are to provide an exact estimate of the radiation dose absorbed by the gland, take account of several factors: age, gender, disease severity and inter- and intra-subject variation in thyroid metabolism under Graves’ disease [87].

    • Hypothyroidism and its associated factors after radioactive iodine therapy among patients with hyperthyroidism in the Northeast Coast State of Malaysia

      2018, Journal of Taibah University Medical Sciences
      Citation Excerpt :

      RAI therapy destroys the thyroid tissue and renders patients either euthyroid or hypothyroid.9 Most often, hypothyroidism is a long-term effect of RAI that necessitates life-long thyroxine supplementation.8 Hypothyroidism frequently develops in the first year after treatment.

    • Graves' disease: A review of surgical indications, management, and complications in a cohort of 59 patients

      2015, International Journal of Oral and Maxillofacial Surgery
      Citation Excerpt :

      A significant number of patients with Graves’ disease are young females with children or who are planning for pregnancy. Although radioactive iodine therapy has not been proved to have any adverse effects on female fertility or adverse effects on the foetus, it is recommended that pregnancy is delayed for at least 6 months after treatment.16 This fact has probably made women planning for pregnancy more reluctant to receive treatment with radioactive iodine.

    • Fluorescent imaging of cancerous tissues for targeted surgery

      2014, Advanced Drug Delivery Reviews
      Citation Excerpt :

      Intensity-modulated radiation therapy and image-guided radiation therapy are two such targeted radiotherapy strategies, and they allow further dose escalation and a reduction in normal tissue radiation exposure [4,5]. Moreover, therapeutic radiation on the molecular scale has further expanded the application of targeted radiotherapy through delivering radioactivity specifically to cancer cells by targeting cancer biomarkers, molecular pathways, or gene expression [6–9]. Similarly, the targets of targeted radiotherapy are either tumor foci or specific molecular or genetic characteristics of cancer, and the impetus for driving the field forward is an improvement in imaging and radiation technology.

    • Non-neoplastic lesions of the thyroid gland

      2012, Head and Neck Pathology: Second Edition
    View all citing articles on Scopus

    Address reprint requests to Michael M. Kaplan, MD, Associated Endocrinologists, 6900 Orchard Lake Road, Suite 203, West Bloomfield, MI 48322

    View full text
    Copyright © 1998 W. B. Saunders Company. Published by Elsevier Inc. All rights reserved.