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Summer Widner, Stephanie Timbs, James Gaugler and James Avenell of ORNL are part of a team that processes thorium-228, a byproduct of actinium-227. As new uses for thorium are realized, particularly in medicine, the lab expects the demand for the radioisotope to grow.

As a medical isotope, thorium-228 has a lot of potential — and Oak Ridge National Laboratory produces a lot.

From left, ORNL’s Rick Lowden, Chris Bryan and Jim Kiggans were troubled that target discs of a material needed to produce Mo-99 using an accelerator could deform after irradiation and get stuck in their holder.

“Made in the USA.” That can now be said of the radioactive isotope molybdenum-99 (Mo-99), last made in the United States in the late 1980s. Its short-lived decay product, technetium-99m (Tc-99m), is the most widely used radioisotope in medical diagnostic imaging. Tc-99m is best known ...