The Australian Nuclear Science and Technology Organisation (Ansto) on 22 June shut down the Opal reactor at its Lucas Heights facility, which usually produces about 10,000 doses a week of Technetium-99m (Tc-99m). An Ansto spokesman said production was temporarily suspended “after a mechanical fault was identified with a piece of equipment”. There was no safety risk due to the stoppage, he said. “Engineers started working to rectify the mechanical fault over the weekend, and remain on site, and will fix it as soon as possible.”

Meanwhile, Ansto has sent supplies of the parent isotope – Molybdenum-99 (Mo-99) – to the US for further processing and is expecting to receive supplies back shortly. It says the impact of the shortage will depend on stock levels in hospitals around Australia. “Nuclear medicine production is one of the most complex production processes in Australia today,” the spokesperson said.

“Just like with any other production process, there are occasional mechanical faults, and if those happen we work closely with our international partners to minimise [damage].” Lucas Heights is only one of 11 reactors around the world that produces nuclear isotopes for medical imaging and treatment. As well as providing about 85% of the nuclear medicine products used in Australian hospitals, Lucas Heights also produces many thousand more doses of Molybdenum-99 each week for international patients. Ansto is in the process of increasing its production capacity to 10m doses a year, enough to meet a quarter of the world’s demand.