This month, a Canadian supplier will discontinue production of a critical isotope widely used for SPECT studies, which has sparked widespread concern about an impending shortage.

The supplier, Chalk River, runs a nuclear reactor that processes molybdenum-99 (Mo-99), the parent isotope of technetium-99m (Tc-99m), which is the primary isotope used for these exams. Chalk River is the only North American supplier, and their exit leaves only six suppliers globally.