Which situation could require the administration of radioactive iodine as an appropriate therapy?

Which situation could require the administration of radioactive iodine as an appropriate therapy?

• A. Hyperthyroidism treated with Graves' disease
• B. Acute radiation syndrome from external exposure
• C. Differentiated thyroid cancer after thyroidectomy
• D. Non-thyroid cancers

Answer: (C)

Radioactive iodine therapy works because thyroid cells uniquely take up iodine, so a radioactive form can deliver targeted radiation to those cells. In differentiated thyroid cancer after thyroidectomy, residual thyroid tissue and any microscopic metastases can still absorb iodine. Administering radioactive iodine ablates this remaining tissue and treats occult spread, helping reduce recurrence and improve disease control. To maximize uptake, the patient is prepared to raise TSH levels, typically by hormone withdrawal or with recombinant TSH, so cancer cells take in more iodine. After treatment, some isolation or radiation safety precautions may be needed and there can be mild side effects like glandular swelling or dry mouth. Other scenarios described do not rely on iodine uptake by cancer cells, so they’re not the typical use case for this therapy.

Radioactive iodine therapy works because thyroid cells uniquely take up iodine, so a radioactive form can deliver targeted radiation to those cells. In differentiated thyroid cancer after thyroidectomy, residual thyroid tissue and any microscopic metastases can still absorb iodine. Administering radioactive iodine ablates this remaining tissue and treats occult spread, helping reduce recurrence and improve disease control. To maximize uptake, the patient is prepared to raise TSH levels, typically by hormone withdrawal or with recombinant TSH, so cancer cells take in more iodine. After treatment, some isolation or radiation safety precautions may be needed and there can be mild side effects like glandular swelling or dry mouth. Other scenarios described do not rely on iodine uptake by cancer cells, so they’re not the typical use case for this therapy.