What is radioactive iodine?
Radioactive iodine is a highly effective treatment option, increasingly preferred over surgery for permanent management of hyperthyroidism. It is absorbed by the thyroid gland, where it destroys thyroid cells, reducing hormone production and potentially shrinking the gland.
When is radioactive iodine treatment used?
Is it safe to conceive after radioactive iodine treatment?
Men should avoid fathering a child for at least six months after treatment, and women should avoid pregnancy for at least six months.
Who should NOT receive radioactive iodine treatment?
Radioactive iodine is not suitable for:
Antithyroid drugs are typically prescribed to stabilize thyroid function before treatment.
How is radioactive iodine administered?
Your procedure will occur in a hospital setting, but inpatient admission is not required. Before administering radioactive iodine, the treatment process and potential side effects will be thoroughly explained at the facility, and your informed consent will be obtained. The dose is delivered either as an easy-to-swallow capsule or liquid form. For effectiveness, the thyroid must be active, so antithyroid medications are typically discontinued at least seven days prior, with specific guidance provided on timing. Beta-blockers may also be prescribed to manage any short-term hyperthyroid symptoms. Your physician will advise whether to resume medication post-treatment and the appropriate timing.
What happens after radioactive iodine treatment?
Follow-up is critical after treatment. Approximately 10% of patients may require an additional dose, with no extra risks associated with repeat treatments. Some patients may need antithyroid drugs for weeks or months until the treatment fully controls thyroid overactivity.
Over two-thirds of patients develop hypothyroidism (underactive thyroid) within one month to a year after treatment, with regular monitoring required. Blood tests are recommended 4–6 weeks post-treatment, then every 1–3 months in the first year, typically at a hospital clinic. Annual blood tests with your GP are advised thereafter, or earlier if hypothyroidism symptoms appear. Hypothyroidism is generally managed effectively with levothyroxine, a thyroxine replacement tablet.
Radioactive iodine treatment for children and teenagers
This treatment is safe and effective for children and teenagers with hyperthyroidism but is typically used as a second-line option after prolonged antithyroid medication. It is less commonly used in younger children.
What is I-131 treatment?
I-131 is a radioactive substance absorbed by specific thyroid cancer cells, destroying them. It is effective for differentiated thyroid cancer. Unabsorbed I-131 is eliminated from the body through sweat, saliva, urine, and stool, while the portion trapped in cancer cells is also eventually cleared.
Investigations required for treatment
How should the patient prepare for I-131 treatment?
Stop thyroid hormone tablets or iodine-containing preparations four weeks before treatment.
How is I-131 treatment administered?
Patients should avoid eating for at least two hours before treatment. I-131 is given as a liquid (via a straw) or capsules. Eating should be avoided for at least two hours post-treatment, if possible.
Are there any side effects?
Possible side effects include mild nausea, neck swelling, and salivary gland tenderness. Long-term risks include hypothyroidism and a slight increase in cancer risk due to radiation exposure. In cases where thyroid cancer extensively affects the lungs, potential risks include pulmonary fibrosis, pulmonary edema, or radiation pneumonitis.
What is Lu-177 DOTATATE treatment?
Lu-177 is a radioactive substance combined with a carrier called DOTATATE. The radioactive Lutetium-177 attaches to octreotate, which binds to neuroendocrine tumor cells, destroying them. It is effective for neuroendocrine tumors, paragangliomas, neuroblastomas, and certain thyroid cancers. Unabsorbed Lu-177 DOTATATE is excreted through sweat, saliva, urine, and stool, and the portion trapped in tumor cells is also cleared from the body.
Investigations required for treatment
Preparation for Lu-177 DOTATATE treatment
Stop depot somatostatin analogue preparations four weeks before treatment. Subcutaneous octreotide (100 mg three times daily, adjusted for symptom control) may be used in the interim.
How is Lu-177 DOTATATE treatment administered?
Anti-nausea medication is provided before treatment. The therapy is delivered via an intravenous drip over one hour, accompanied by a four-hour infusion of an amino acid solution to protect the kidneys from radiation. The Lu-177 DOTATATE infusion takes 60 minutes.
What is Lu-177 PSMA treatment?
Lu-177 is a radioactive substance linked to prostate-specific membrane antigen (PSMA). The PSMA carrier binds to prostate tumor cells, allowing the radioactive Lutetium-177 to destroy them. It is effective for prostate cancer. Unabsorbed Lu-177 PSMA is eliminated through sweat, saliva, urine, and stool, and the portion trapped in tumor cells is also cleared from the body.
Investigations required for treatment
Preparation for Lu-177 PSMA treatment
Pause taxane-based chemotherapy for at least four weeks before treatment.
How is Lu-177 PSMA treatment administered?
Anti-nausea medication is given before treatment. The therapy is administered via an intravenous drip over 30–60 minutes, along with a normal saline drip and a diuretic injection.
Are there any side effects?
The most common side effect is nausea, mitigated by pre-treatment injections and take-home tablets. Other potential side effects include: