From the Research
Sodium-131 (I-131) treatment is a highly effective radioactive iodine therapy for treating thyroid conditions, including hyperthyroidism and thyroid cancer, with a recommended dose of 1.11 GBq (30 mCi) for remnant ablation, as suggested by the American Thyroid Association (ATA) and other medical societies 1.
Overview of Sodium-131 Treatment
Sodium-131 (I-131) treatment is primarily used to treat thyroid conditions, including hyperthyroidism and thyroid cancer. The treatment involves administering a single dose of radioactive iodine orally, either in capsule or liquid form.
- The typical dose ranges from 10-30 millicuries for hyperthyroidism and 30-200 millicuries for thyroid cancer.
- Before treatment, patients should stop taking thyroid medications for 1-2 weeks, avoid iodine-rich foods, and undergo pregnancy testing if applicable.
- After treatment, patients must follow radiation safety precautions for 3-7 days, including limiting close contact with others (especially children and pregnant women), using separate utensils, and sleeping alone.
Side Effects and Mechanism
Side effects may include temporary neck tenderness, nausea, dry mouth, altered taste, and rarely, inflammation of salivary glands.
- This treatment works because thyroid tissue naturally absorbs iodine, allowing the radioactive I-131 to concentrate in thyroid cells where it emits radiation that destroys these cells while minimizing damage to surrounding tissues.
- Regular follow-up appointments are essential to monitor thyroid function and adjust any subsequent medication needs.
Recent Guidelines and Recommendations
Recent studies have shown an increased concern for the development of secondary cancers as a result of radioactive iodine treatment, with some reports indicating that cumulative RAI doses exceeding 5.6-7.4 GBq (150-200 mCi) were found to represent an increased risk for developing secondary primary malignancies (SPM) 1.
- However, a clearly defined dose threshold cannot be provided based on the current literature.
- Nonetheless, caution should be exercised when considering repeated RAI therapies for persistent metastatic disease, with a cumulative dose exceeding 37.0 GBq (1,000 mCi), due to the potential risk of developing SPM and other long-term toxicity.
- The choice of treatment depends on the underlying diagnosis, the presence of contraindications to a particular treatment modality, the severity of hyperthyroidism, and the patient's preference, as stated in the American Family Physician journal 2.