What is the primary use of Iodine-131 in nuclear medicine?

Iodine-131 is primarily utilized in the treatment of hyperthyroidism and thyroid cancer due to its ability to selectively accumulate in thyroid tissue. This radioisotope emits both beta and gamma radiation, which allows it to efficiently destroy overactive thyroid cells while minimizing harm to surrounding healthy tissue. In patients with hyperthyroidism, the high levels of iodine uptake by the overactive thyroid gland facilitate targeted therapy, leading to a decrease in thyroid hormone production.

In the context of thyroid cancer, Iodine-131 serves a dual purpose: it not only helps in the ablation of remaining thyroid tissue post-surgery to prevent cancer recurrence but also provides a means for detection of metastatic disease through scintigraphy. This unique property of Iodine-131 to both treat and diagnose thyroid-related conditions reinforces its primary role in nuclear medicine regarding thyroid disorders.

Other isotopes and radiopharmaceuticals are better suited for cardiac imaging, monitoring blood flow in the kidneys, or conducting bone scans, as they have distinct mechanisms of action, biodistribution, and radiation emissions that cater specifically to those needs. Thus, while those other choices hold relevance in different aspects of nuclear medicine, they do not align with the primary function of Iodine-131, which remains focused