I-131

Iodine-131 (I-131) is a radioactive isotope of iodine with a half-life of approximately 8 days. It decays by beta emission and gamma radiation, making it useful for both therapeutic and diagnostic purposes. I-131 is produced artificially in nuclear reactors as a fission product of uranium or by neutron irradiation of tellurium.

I-131 is widely used in nuclear medicine, particularly for the treatment of thyroid disorders. It is a key component in the treatment of hyperthyroidism and thyroid cancer, where it selectively targets thyroid tissue due to the thyroid gland's natural ability to absorb iodine. I-131 is also used in diagnostic imaging of thyroid function and as a tracer in certain radiopharmaceuticals. Additionally, I-131 has applications in radiation therapy for other cancers and in scientific research to study iodine metabolism and biological processes.

I-131 does not occur naturally in significant quantities and is produced in nuclear reactors as a fission product of uranium or during neutron activation of tellurium. It is encountered in controlled environments such as medical facilities, research laboratories, and occasionally in areas affected by nuclear activities or accidents. Due to its radiological properties, the use and handling of I-131 are strictly regulated to ensure safety for patients and professionals. It is also monitored in the environment as a potential contaminant following nuclear power plant operations or incidents.