This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Which is/are false about T1/2 of radioisotopes \nSelect and explain. \nA. Ra-226: 1626 years, B. I-131: 60 years, C. Co-60: 5.26 years, D. Ir-192 : 74 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Iodine-131 (131I) is an important radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days.\nIt is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas production.\nIt also plays a major role as a radioactive isotope present in nuclear fission products, and was a significant contributor to the health hazards from open-air atomic bomb testing in the 1950s, and from the Chernobyl disaster, as well as being a large fraction of the contamination hazard in the first weeks in the Fukushima nuclear crisis.\nThis is because I-131 is a major fission product of uranium and plutonium, comprising nearly 3% of the total products of fission (by weight).\nSee fission product yield for a comparison with other radioactive fission products. I-131 is also a major fission product of uranium-233, produced from thorium.', 'role': 'assistant'}]