The shipment, which contained a quantity of Sodium-22 (22Na), was stopped by Russian customs officials for some unknown reason. Though initially reported as something that could “only be created in a nuclear reactor officials later corrected this to confirm that it was not only not exclusive to reactors but not commonly created within them, and instead is mostly created in particle accelerators and research reactors in university and medical environments.
Of course it has been well established that Iran has been extremely low on fuel for its US-built Tehran Research Reactor, which produces materially all of the nation’s medical isotopes, and while Western officials have been putting the screws to them on acquiring more fuel for it, it isn’t hard to guess why Iranians would be trying to import the isotopes. Cancer, after all, continues even when sanctions are in place, and it isn’t surprising that Iran wasn’t content to abandon nuclear medicine. The real question is why Russia had such a problem with the export of a quantity of the isotope.