International Isotopes Inc. manufactures and sells nuclear medicine calibration and reference standards, cobalt-60 products, sodium iodide I-131 drug product, and radiochemicals for clinical research and life sciences in the United States and internationally. It operates through four segments: Nuclear Medicine Standards, Cobalt Products, Theranostics Products, and Fluorine Products. The Nuclear Medicine Standards segment manufactures sources and standards associated with single photon emission computed and positron emission tomography imaging, patient positioning, and calibration or operational testing of dose measuring equipment for the nuclear pharmacy industry. This segment also offers flood sources, dose calibrators, rod sources, line sources, flexible and rigid rulers, spot markers, pen point markers, and various specialty design items. The Cobalt Products segment produces bulk cobalt; fabricates cobalt capsules for radiation therapy and various industrial applications; and recycles expended cobalt sources. The Theranostics Products segment produces and distributes Iodine-131 generic drug product and various isotopically pure radiochemicals for medical, industrial, or research applications. The Fluorine Products segment is involved in the production of small-scale qualification samples of high purity fluoride gas for various industrial applications, as well as development of laboratory and analytical processes required to support the planned uranium de-conversion and fluorine extraction facility. The company sells its products directly to end users and distributors. International Isotopes Inc. was incorporated in 1995 and is headquartered in Idaho Falls, Idaho.