Radioiodine Therapy (131I)

Your doctor may recommend radioiodine therapy for:

• Hyperthyroidism: To reduce the overproduction of thyroid hormones, often due to conditions like Graves’ disease or hyperactive thyroid nodules.
• Thyroid Cancer: To destroy any remaining cancerous thyroid tissue after surgery or to treat thyroid cancer that has metastasised to other areas.

• Radioiodine dose: Radioiodine is usually taken as a pill or liquid, which you will swallow in a single dose. It is tasteless and well-tolerated by the body.
• Absorption by thyroid: The radioactive iodine is absorbed by your thyroid gland over the next few days to months, when it destroys the targeted thyroid cells and reduces overactivity.
• Follow-up: You may be asked to come back for follow-up blood tests or scans to assess how well the therapy is working.

• Administration of radioiodine: a few minutes (single dose)
• Absorption and effect: over days to months
• Hospital stay: usually not required, but sometimes a short isolation period may be needed depending on the dose
   

• Low-iodine diet: You may be asked to follow a low-iodine diet for 1-2 weeks before treatment to help the thyroid gland absorb the radioiodine more effectively. This involves avoiding foods like dairy products, seafood, iodised salt, and processed foods that contain iodine.
• Medications: Inform your doctor about any medications you are taking, especially thyroid medications. Some medications may need to be stopped temporarily before treatment.
• Pregnancy and breastfeeding: Radioiodine therapy is not suitable for pregnant or breastfeeding women. You should avoid trying to conceive for at least 6 months after the treatment, and breastfeeding should be stopped prior to therapy.
• Plan for isolation: After treatment, you may need to limit close contact with others, especially children and pregnant women, for a few days due to the radiation. The exact duration will depend on the dosage of radioiodine.

• Radiation precautions: After receiving radioiodine therapy, you will emit small amounts of radiation. You need to follow specific safety guidelines for a few days to minimise radiation exposure to others. To protect those around you, follow these precautions for a few days after treatment:
  • Limit close contact: Avoid prolonged physical contact with others, especially, pregnant women and young children.
  • Sleep separately: Sleep in a separate bed, if possible, for a few days.
  • Use separate utensils and dishes: Wash your utensils and dishes separately from others.
  • Flush the toilet twice: After using the bathroom, flush the toilet twice and wash your hands thoroughly.
  • Avoid public places: Stay away from crowded areas and public transportation to reduce exposure to others.
• Your doctor will guide you on the exact duration based on your dose.
• Most patients can return to their routine in a few days.