The Medical Isotope ProjectVersion française
The Canadian Light Source’s Medical Isotopes Project (MIP) produces molybdenum-99 (Mo-99) – the parent isotope of Tc-99m – from the stable isotope, molybdenum-100 (Mo-100).
How does MIP work?
The MIP facility produces Mo-99 using a process called photo-neutron reaction. An electron accelerator bombards a target made of Mo-100 metal, producing high-energy X-rays. The X-rays then convert Mo-100 atoms into Mo-99 isotopes by knocking out one neutron from the atom. The Mo-99 decays into Tc-99m that is used for tagging radiopharmaceuticals for medical diagnostic tests. After the Mo-99 has decayed, the remaining Mo-100 is recovered and recycled into new targets (See diagram).
Diagram of the proposed process. An electron beam from a linear accelerator is used to produce high-energy X-rays. X-rays shine on a target consisting of molybdenum-100 (Mo-100) discs. An X-ray strikes the nucleus of a Mo-100 atom, knocking away a neutron to create molybdenum-99 (Mo-99), which decays to become technetium-99m (Tc-99m). A radionuclide separator separates the Tc-99m from the Mo-100 so that it can be injected into patients undergoing medical tests. The Mo-100 can then be recycled into new targets.
On June 2, 2010, the Government of Canada announced the $35 million Non-reactor-based Isotope Supply Contribution Program (NISP) to promote research into alternative methods for producing medical isotopes to address the shortage of technetium-99m (Tc-99m) in Canada due to ongoing difficulties with the National Research Universal (NRU) reactor.
The CLS led a proposal for the MIP along with the National Research Council of Canada, University of Ottawa Heart Institute and Toronto’s University Health Network to investigate the technical and economic feasibility of using an electron linear accelerator to produce Mo-99 from Mo-100.In January 2011, the CLS-led NISP project received $10 million from Natural Resources Canada with an additional $2 million from the Province of Saskatchewan.
In February 2013, the Government of Canada announced the Isotope Technology Acceleration Program (ITAP), a $25-million four-year program to further advance cyclotron and linear accelerator technologies for the production of Tc-99m. The program supports collaboration among academic, private and public sector partners, and the work needed to attract private sector interest to help ensure that isotope production is reliable and on a sound commercial footing. Under this program, the Prairie Isotope Production Enterprise (PIPE) was awarded $7.46 million over four years to bring linear accelerator production of Mo-99 and Tc-99m to the market by 2016. Using infrastructure developed under the NISP, the CLS supplies PIPE with Mo-99. PIPE is a not-for-profit corporation based in Manitoba, whose goal is to develop a reliable supply of Tc-99m for Canadian patients.
What are isotopes?
Isotopes are atoms of the same element with differing numbers of neutrons in their nuclei. Stable isotopes of an element do not change over time. Atoms of unstable isotopes – also called radioisotopes – change into other elements over time through radioactive decay. Radioisotopes are used in many medical imaging and diagnostic procedures, with the isotope Tc-99m being used in 80 percent of tests. In Canada alone, Tc-99m is used in approximately 5,500 medical scans a day.
Who else makes radioisotopes?
Most radioisotopes are produced in a small number of aging nuclear research reactors around the world, as by-products from the fission of highly enriched, weapons grade uranium. In the case of Tc-99m, Mo-99 is collected from the by-products of the fission of uranium atoms, and packaged for shipment to hospitals around the world. The Mo-99, with a half-life of 66 hours, decays into Tc-99m, which has a half-life of 6 hours.
Using nuclear reactors to produce medical isotopes come with a number of challenges. Aging reactors are becoming increasingly unreliable and outages contribute to ongoing shortages. The use of highly enriched uranium is also a major security and proliferation concern, with many nations, including the United States, actively working to eliminate its use in civilian applications. Since half of the Mo-99 decays every 66 hours, much of the resulting Tc-99m ends up being wasted as it decays during shipment from far-flung reactors, to distribution companies, and finally to hospitals. Uranium fission in reactors also creates other radioactive by-products besides Mo-99 that persist as long-lived nuclear waste.
How will this project solve the isotope shortage?
The MIP linear accelerator produces Mo-99, providing for diversity and redundancy in the supply chain. This facility will produce enough medical isotopes to meet the needs of Saskatchewan and Manitoba. It is expected that a few similar facilities will be able to meet Canadian demand.
How does this project solve the drawbacks of using nuclear reactors to make isotopes?
Unlike reactor-based production which usually uses highly enriched uranium the CLS linac produces Mo-99 – the parent isotope of Tc-99m - directly from Mo-100 targets by removing a single neutron from each atom. By taking uranium out of the production equation, concerns about security, proliferation and long-lived nuclear waste by-products are eliminated.
CLS will supply PIPE with the Mo-99, from which the Winnipeg Regional Health Authority will extract the Tc-99m, test its purification and conduct clinical trials to demonstrate its use and efficacy in nuclear medicine diagnostic tests for cancers and heart disease. The objective is to license the purified isotope for patient use through Health Canada, and to become a regional supplier of the isotope for healthcare facilities across western Canada and northern Ontario by 2016.
CLS, PIPE, and their partners, will continue to work together to expand this unique and first-in-the-world technology, to ensure sustainable secure access to medical isotopes for all Canadians. In addition, through commercialization and spin off opportunities, the partners plan to export this made-in-Canada technology around the world, creating new Canadian businesses and jobs.
This project would not have been possible without essential contributions from these partners.
- NRC Ottawa (ON)
- NRC Boucherville (PQ)
- Mevex (Stittsville, ON)
- RMD (Saskatoon, SK)
- Acsion Industries (Pinawa, MB)
- Winnipeg Regional Health Authority’s Health Sciences Centre Winnipeg (Winnipeg, MB)
- University of Winnipeg (Winnipeg, MB)