The most commonly-used medical isotope, technetium-99m (99mTc) (half-life 6 hours), is derived from its parent, molybdenum-99 (99Mo) (half-life 2.7 days), which is currently produced in a few aging nuclear reactors. This supply chain is becoming increasingly fragile and when a major reactor is removed from service unexpectedly or for planned maintenance, a world-wide medical isotope shortage may result.
Natural Resources Canada’s Non-reactor-based Isotope Supply Contribution Program (NISP) will contribute $11 million in support of the Advanced Cyclotron Systems Inc. (ACSI) led project “Commercializing Cyclotron Production of 99mTc in Canada”. During the initial phase of the NISP project two pilot cyclotron facilities, at the Centre Hospitalier Universitaire de Sherbrooke (CHUS) and the University of Alberta, will demonstrate the technological, regulatory and commercial foundation for high-level cyclotron-based 99mTc production technology that, between 2012 and 2014, would become a viable alternative source of 99mTc. Our fourth partner, Thunder Bay Regional Research Institute, (TBRRI) who is planning to establish a TR-24 Cyclotron Facility in the near future, will also be an important participant in this Research and Development program.
CHUS and the University of Alberta have secured substantial funding from other federal, provincial and independent sources for the construction of new cyclotron facilities. The NISP funding will leverage these investments to upgrade equipment and infrastructure to develop the 99mTc production technologies. Beyond the NISP, the plan is for two pilot production facilities equipped with high power TR-24 commercial cyclotrons to begin production of 99mTc for distribution to local hospitals. It is estimated that each site would be able to supply up to 15% of Canadian requirements. This source of medical isotopes would be independent of existing supply chains and provide redundancy and emergency backup. These facilities will also be capable of producing other radioisotopes, most notably for Positron Emission Tomography (PET) radiopharmaceuticals, thus ensuring that this investment will be well-utilized, producing a complete range of radiopharmaceuticals for PET and Single Photon Emission Computed Tomography (SPECT) applications.
This project builds on important work already proposed and published by a network or researchers across Canada. In July 2009, ACSI, together with several Canadian universities and research centres, proposed to develop commercial-scale production of 99mTc in Canada using cyclotrons as an alternative to reactor produced 99Mo and 99mTc. This could be accomplished through a national network of several strategically placed medium-energy cyclotrons capable of supplying much of Canada’s nuclear medicine isotope needs, including, but not limited to, 99mTc. This network would exploit the centralized radiopharmacy model that is currently employed across Canada for the preparation and distribution of both PET and SPECT radiopharmaceuticals. In this model 99mTc produced on cyclotrons would replace the 99mTc from 99Mo/99mTc generators, but the subsequent preparation and distribution of individual patient doses would remain identical to current practices; only the source of the radioisotope would change.
ACSI, the CHUS and the University of Alberta started preliminary experiments in the fall of 2009 and continued work under Canadian Institutes of Health Research / Natural Sciences and Engineering Research Council of Canada’s Collaborative Health Research Projects Program, in collaboration with other Canadian Institutions. Significant progress has been made in target and process development (Guérin 2010). Curie amounts of 99mTc were made available from existing cyclotrons at the CHUS and the University of Alberta. The research and development activities will now be focused on the development of commercial, cost efficient production of 99mTc using high-current 24 MeV cyclotrons manufactured in Canada by ACSI.
Planned and Potential Cyclotron Production Facilities and their Geographic Reach
Easily Scalable, Adaptable and Reliable
Cyclotron-based production of medical isotopes is a very flexible approach; as the Canadian demand for 99mTc increases, more sites can be added and/or production can be increased at the proposed sites. Furthermore, when the 99mTc production demands have been satisfied, the cyclotron network can be used to supply the continuously growing number of alternative PET/SPECT medical isotopes. This type of flexibility and adaptability is not possible with reactor-based production methods.
The decentralized “network” approach is intrinsically more reliable as production is not dependent on any one facility. There would be enough excess capacity in the overall network to cover local shortages.
Diversification, Innovation and Future Growth
A network of cyclotron centres would not only supply 99mTc, but would also have the capacity to provide a full spectrum of PET and SPECT radioisotopes such as 18F, 64Cu, 123I, 124I, 68Ge and others. This capacity would help to ensure future growth and diversity of nuclear medicine in Canada, as well as to facilitate research and innovation. The cyclotron technology would lessen the financial, social and political issues inherent in the production of medical isotopes via highly enriched uranium targets and fuelled reactors. It would effectively remove the nuclear medicine community from the multi-faceted debates concerning the construction, maintenance, waste generation and disposal and ultimately the decommissioning of these facilities.
Solution is Entirely Canadian
The proposed technology is a true “made in Canada” solution; the manufacture of the cyclotrons as well as the actual production of the medical isotopes and their subsequent distribution will be done by Canadian companies and institutions. Implementing the proposed model will strengthen Canada’s position as a world leader in nuclear medicine and will provide long-term benefits for the Canadian economy and health care system.
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