Final answer:
Iodine-131 is used in medical imaging and treatment of thyroid diseases, decaying by beta emission with a half-life of approximately 8 days, eventually leaving the patient's system.
Step-by-step explanation:
The statement accurately describes the use of Iodine-131 (I-131) for imaging the thyroid gland and its decay by β− emission, with a half-life of approximately 8 days. I-131 therapy involves administering small doses of the isotope to a patient, which the thyroid absorbs.
The emitted radiation from the concentrated I-131 creates an image of the thyroid on a film and is also used for treating conditions like hyperthyroidism or thyroid cancer.
Due to its decay characteristics, I-131 eventually leaves the patient's system after a few weeks, reducing the risk of long-term radiation exposure. The isotope eventually decays to xenon-131, emitting an electron in the process.