NCI Drug Dictionary
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iodine I 123
A radioactive isotope of iodine, a nonmetallic element of the halogen group with an atomic mass of 123 and a half-life of 13.2 hours with radioisotopic activity. Selectively accumulating in the thyroid tissue, iodine I 123 emits gamma rays that can be detected with gamma scintigraphy, allowing localization of thyroid tissue. This agent may be used as a tracer in whole body scintigraphy (WBS) to localize thyroid carcinoma metastases. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus)