isotopeKK [ˋaɪsəˏtop] /ˈaɪsəˌtoʊp/名詞1同位素Carbon has several isotopes, one of which is used for dating fossils.碳有好幾種同位素,其中一種可用來測定化石的年代。2放射性同位素醫學Doctors inject a small amount of a radioactive isotope before the scan.醫生會在掃描前注射少量的放射性同位素。