MURR is the only supplier of I 131 in the United States and the first U.S. supplier since the 1980s. Image courtesy of University of Missouri
November 13, 2018 — The University of Missouri Research Reactor (MURR) recently shipped its first batch of Iodine-131 (I-131), a radioisotope widely used for diagnosing and treating thyroid cancer and hyperthyroidism. The shipment makes MURR the only supplier of I-131 in the United States and the first U.S. supplier since the 1980s.
According to the American Cancer Society, thyroid cancer is “the most rapidly increasing cancer in the U.S.,”1 with diagnoses tripling in the last three decades. There will be an estimated 53,990 new cases of thyroid cancer in the U.S. in 2018 with an estimated 2,060 deaths from the disease, according to the National Cancer Institute. A domestic supply of I-131 is vital due to increasing demand and the isotope’s short shelf-life, according to MURR.
“Supplying I‑131 is part of a strategic initiative by the University of Missouri and MURR to address medical isotope shortages and further the University’s research mission,” said David Robertson, executive director of MURR.
I-131 sodium iodide became the first U.S. Food and Drug Administration (FDA)-approved radiopharmaceutical in 1951 and is one of the most widely used radiopharmaceuticals in the United States. The isotope’s unique properties enable both diagnostic imaging and treatment of cancer and hyperthyroidism. Since the thyroid gland naturally absorbs iodine, I‑131 can be targeted directly to thyroid tumors to remove cancerous tissue and treat the disease.
With only an eight-day half-life, stockpiling I-131 is impossible and logistics are complicated, making a reliable supplier critical for patients. MURR is one of only a handful of research reactors around the world that supply I-131 to drug manufacturers who, in turn, supply radiopharmaceuticals for distribution to hospitals and patients.
I-131 joins a growing lineup of isotope active ingredients supplied by MURR for radiopharmaceuticals including Therasphere, Quadramet and Lutathera, which was recently approved by the FDA to treat pancreatic cancer.
For more information: www.murr.missouri.edu
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November 12, 2025 
