Iodine I-131

**Semantic type:** Element, Ion, or Isotope|Indicator, Reagent, or Diagnostic Aid|Pharmacologic Substance

**Definition:** A radioactive isotope of iodine with an atomic mass of 131, a half life of eight days, and potential antineoplastic activity. Selectively accumulating in the thyroid gland, iodine I 131 emits beta and gamma particles, thereby killing thyroid cells and decreasing thyroid hormone production.

**Synonyms:** - 131-Iodine - Bound Iodide I-131 - I 131 - I-131 - IODINE I-131 - Iodide I-131 - Iodide, I-131 - Iodine 131 - Iodine-131 - Iodine-131 - Iodotope - Iodotrope