1 Nov (NucNet): Coordinated action has reduced worldwide shortages of medical isotopes, but supply vulnerabilities remain because of the small number of participating organisations at some steps in the supply chain, a report by the US National Academies says.
The report says action taken by governments and suppliers since supply shortages in 2009 and 2010 has improved the resilience of the global supply chain, minimised supply disruptions during unplanned reactor and processing facility shutdowns, and increased efficiencies in the way the isotopes are used.
Technetium-99m (Tc-99m), the decay product of molybdenum-99 (Mo-99), is the most widely used radionuclide for medical imaging and is produced in a number of research reactors, although none of these reactors are in the US.
The report says Mo-99 production has been “disrupted unexpectedly on numerous occasions” since 2009. Some of these disruptions resulted in severe supply shortages in the US and other countries.
Disruptions in 2009 and 2010 occurred when Canada’s NRU and the HFR reactor at Petten in the Netherlands, were simultaneously shut down for extended periods. These shutdowns caused major disruptions in Mo-99 supplies and in diagnostic imaging procedures in some countries. Supply interruptions have also occurred as a result of transportation denials and delays.
Several actions have been taken since the 2009-2010 supply shortages to improve the resilience of the Mo-99 supply chain, notably the development of the “outage reserve capacity “, or ORC, which makes reactors available at short notice to fill supply gaps.
There are a number of ways to create this reserve capacity, the report says. For example, additional days in a reactor’s schedule can be dedicated for the irradiation of targets, or the number of available positions in the reactor used to irradiate targets can be increased.
There has also been improved coordination of reactor and target processing facility outages, improved communications among supply chain participants, and the creation of Mo-99 supplier alliances.
In spite of these actions, however, vulnerabilities remain in some parts of the supply chain. This is particularly true for the front end of the supply chain, where one company, Cerca, provides most of the targets used to produce Mo-99. This large market share also gives this manufacturer strong pricing power. The relatively small number of global Mo-99 suppliers is another potential point of vulnerability.
The report says the US consumes about half of the world’s supply of Mo-99, but there has been no domestic production of this isotope since the late 1980s. The US imports Mo-99 for domestic use from Australia, Canada, Europe, and South Africa.
Mo-99 and Tc-99m cannot be stockpiled for use because of their short half-lives. Consequently, they must be routinely produced and delivered to medical imaging centres. Almost all Mo-99 for medical use is produced by irradiating highly enriched uranium (HEU) targets in research reactors, several of which are over 50 years old and are approaching the end of their operating lives.
As of June 2016, about 95% of the global supply of Mo-99 for medical use was produced in seven research reactors located in Australia, Canada, Europe, and South Africa and supplied from five target processing facilities in those same locations. The remainder of the global supply is produced in other locations for regional use.
New Mo-99 supplies have become available since 2009, and expansions in available supply capacity are planned by current and new suppliers. A supplier in Australia, the Australian Nuclear Science and Technology Organisation, has entered the global supply market and plans to expand its available supply capacity. Existing global suppliers in Europe (Mallinckrodt) and South Africa (NTP Radioisotopes) have initiated plans to expand their available supply capacities. Russia plans to become a global supplier and capture about a 20% share of the global market using reactors at the Research Institute of Atomic Reactors in Dimitrovgrad.
The American Medical Isotopes Production Act of 2012 and financial support from the Department of Energy’s Nuclear Security Administration have stimulated private-sector efforts to establish US domestic production of Mo-99 for medical use. However, the report says, potential domestic Mo-99 suppliers face technical, financial, regulatory, and market penetration challenges. The market challenges will likely increase after current global suppliers expand production.
The report is online: http://bit.ly/2e9DGPp
