A naturally or artificially produced radioactive isotope of an element.
氯的一种放射性同位素.
互联网
Caesium - 137 is a radioactive isotope, formed mainly through nuclear fission.
铯-137是一种放射性同位素, 主要由核分裂产生.
互联网
A radioactive isotope of cobalt emits penetrating gamma rays that are used in radiation therapy.
曾有人建议用钴的另一种放射性同位素来制造钴弹,但从未发展.
互联网