also: ようそひゃくさんじゅういち
noun
iodine-131
A radioactive isotope of iodine, commonly referenced in nuclear medicine and radiation safety contexts.
ヨウ素１３１は甲状腺に集まりやすい放射性同位体です。
Iodine-131 is a radioactive isotope that tends to accumulate in the thyroid gland.
原発事故
After the nuclear accident, the concentration of iodine-131 in the environment was measured.