A Winning Formula

TRIUMF’s advanced isotope-related research makes its mark in science and medicine

Unbeknownst to most Vancouverites, their city is actually a wellspring of activity for isotope-related research and development. In fact, in scientific circles, Vancouver is rapidly gaining a reputation as the world’s Isotope Valley.

The city’s growing hub of expertise traces back to 1974 when Canada built the world’s largest cyclotron (a particle accelerator capable of producing many kinds of isotopes, or variants of chemical elements) at TRIUMF, a national laboratory for nuclear and particle physics located at the University of B.C. Attracting isotope researchers and experts from far and wide, TRIUMF’s world-renowned cyclotron spawned volumes of groundbreaking isotope-related research in Vancouver, as well as a local industry to support the research community’s activities. Today, TRIUMF’s collaborators include Advanced Cyclotron Systems, Inc. (ACSI) and PAVAC Industries, Inc., both in Richmond, and Nordion, Inc. in Vancouver and Ontario. ACSI is a spinoff from EBCO Industries, which helped build TRIUMF, which now manufactures cyclotron and nuclear parts as one of the world’s biggest suppliers of cyclotrons to hospitals. Best Cyclotron Systems Inc. recently sited its headquarters in Vancouver to be near the burgeoning pool of talent.

TRIUMF now operates a fleet of cyclotrons, producing an impressive catalogue of 10 established isotopes for the laboratory’s collaborators, and has three more under development for use in its own experimental research. “We make some of the well-accepted isotopes that are used in the community but we are also well positioned to look at the next generation of isotopes – where the innovation is going to happen,” explains Paul Schaffer, Ph.D., head of nuclear medicine at TRIUMF.

One innovation TRIUMF has been spearheading the past couple of years is addressing the shortage of an isotope known as technetium-99m. Eighty per cent of the 20 to 40 million nuclear medicine procedures performed in hospitals every year (such as medical imaging and diagnostic scans) require technetium-99m, which is the decay product of molybdenum-99. Currently, the world’s supply of technetium-99m is produced by just five nuclear reactors. But those five reactors—one of which is in Chalk River, Ontario—are aging and facing imminent closure, threatening the supply of technetium-99m to hospitals worldwide. The federal government has opted not to renew the reactor in Chalk River, and so isotope production will cease in 2016, putting a strict deadline on finding an alternative source of the important isotope.

“The technetium project was a natural one for us to take on, since it made use of the skills we had developed here, and we’ve been working with our collaborators on this,” says research engineer Ken Buckley, project manager of a national effort to address the global medical-isotope supply crisis. “Our goal has been to ensure there is a routine and reliable supply of technetium for the nuclear medicine community in Canada.”

And TRIUMF has indeed achieved that goal. Buckley’s team has found a way to adapt small, modern cyclotron devices, which rely on electricity and magnets rather than nuclear fuel to produce the necessary isotope reactions, to create technetium-99m. “Our proposal is to basically move the world from the centralized production model that requires these nuclear reactors to a decentralized production model where numerous cyclotrons already located in hospitals around the world can be used to produce these isotopes for their own facilities,” says Schaffer. Having already perfected the technology, TRIUMF is now in the process of commercializing it for adoption around the world.

In addition to ending its dependence on nuclear reactors, TRIUMF’s isotope research is rapidly advancing the medical field in other ways – especially through the development of radiopharmaceuticals, or radioactive drugs.

Radiopharmaceuticals are radioactive isotopes attached to an active biological agent, such as a sugar molecule, to create a tracer. “We can inject them into the bloodstream and they travel through the body as any drug would, and then they localize based on their pharmaceutical properties,” explains Schaffer. “The exception here is that, because they’re radioactive, we can image them using special cameras in the hospital called PET (positron emission tomography) cameras.”

[pagebreak]The most commonly used tracer is a radioactive form of glucose called FDG, which is taken up into tumours and is useful in diagnosing cancer. TRIUMF works closely with the BC Cancer Agency, supplying specialized isotopes that the BC Cancer Agency cannot produce using its own cyclotron.

The use of tracers has become standard procedure in oncology, but there’s always room for improvement. “There are already several radioactive tracers being used, but some of them are not sensitive to all the different cancers that are out there. So we are delivering the standard tracers for diagnosing cancer and we’re always developing new tracers to diagnose cancer even better,” says research scientist and cyclotron operations coordinator Cornelia Hoehr, Ph.D.

These new tracers also make cancer treatment more efficient. “Nowadays, oncologists don’t want to hammer you with the standard treatment. In many cases, they do a PET scan to figure out where the cancer is, how big it is and whether it has spread already. It’s called staging. Then, after a few weeks of a particular treatment, they do another PET scan to see if the tumour is responding. If not, they change their approach,” explains Hoehr. “Because these PET scans are very sensitive and can figure out if the treatment is working or not, they are saving a lot of time, and also a lot of money – tens of thousands of dollars per patient,” Hoehr adds.

Some of TRIUMF’s latest research centres on finding a safer and more efficient way to produce radio metals, which have the potential to create exceptionally sensitive new tracers, and on developing new isotopes that can be used to both diagnose cancerous tumours and treat them at the same time through the use of alpha particles.

But the use of radioactive tracers extends well beyond cancer diagnostics. Some of the longest-used tracers produced by TRIUMF specifically target a particular neurotransmitter system in the brain called the dopamine system, which is increasingly recognized as playing a part in attention deficit, impulse control and mood disorders. It’s also inextricably linked with many of the symptoms of Parkinson’s Disease, and TRIUMF’s 30-year collaboration with the Pacific Parkinson’s Research Centre has yielded insights into the pathology and progression of Parkinson’s Disease, thanks to the use of a variety of specially developed tracers and PET imaging of the brain.

Other uses for TRIUMF’s radiopharmaceuticals are wide-ranging, including UBC’s psychiatry department’s investigation into how addiction functions within the brain; the botany department’s analysis of the efficacy of rice plant fertilizer; the engineering department’s search for the most effective way to make paper; and the oceanography department’s study of algae growth in the ocean, which ultimately affects the world climate through absorption of CO2 out of the atmosphere.

The applications for isotope-related research are endless, but without an advanced research laboratory like TRIUMF on hand to collaborate with on experimental radiopharmaceuticals or other novel isotope probes for materials, few research communities are able to exploit isotopes to their full potential. “There are lots of labs around the world that make use of isotopes, but they purchase them, and they can only purchase isotopes that have a commercial demand – which can be difficult,” says Buckley. “Here in Vancouver, we have a combination of a research community that makes use of radioisotopes in diverse applications and the expertise to produce those isotopes as well.” Which means that, now more than ever, the world will be looking to Vancouver to lead the way in innovative isotope applications in science and medicine.