UOHI to receive $5.4M federal funds for development of new alternative radioisotope imaging tracers

Nov 10 2009

New Tracers Made On Site with No Requirement for Nuclear Reactor

Researchers from the University of Ottawa Heart Institute (UOHI) will receive nearly half of a $5.4 million federal fund to help solve a shortage of medical isotopes resulting from the shutdown of the Chalk River nuclear reactor. Two research teams will develop two new alternative radioisotope imaging tracers, test new applications for their use in diagnosing heart disease, and fast track production and distribution as quickly as possible across Canada.

Tracers are the radioisotope-labelled pharmaceuticals used to visualize specific disease and treatments by sophisticated imaging technologies. The Heart Institute has the rare capability to produce new, extremely short-lived tracers on site with no requirement for a nuclear reactor. Currently the Heart Institute supplies alternative medical isotopes for the Ottawa Hospital system as a result of shortfalls in Technetium-99m, the principal medical isotope produced at Chalk River, which shut down in May.

Two UOHI research teams were awarded two-year grants worth a total of $2.17 million through the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council of Canada (NSERC). Plans to allocate research funds for novel alternate radiological tracers were announced in June by the Honourable Leona Aglukkaq, Minister of Health.

"We are aware of a heightened need to develop alternatives to the most commonly used radioisotopes. As a national centre for high performance cardiac diagnostic imaging and research, the Heart Institute plays an important role in pioneering a major scientific endeavour that will only improve methods for diagnostic imaging," said Dr. Terrence Ruddy, Chief of Cardiology and Director of Nuclear Cardiology, UOHI.

Dr. Ruddy leads one UOHI research team investigating a new class of Iodine 123 tracers for use in diagnosing coronary artery disease by single photon emission computed tomography (SPECT) imaging. SPECT uses a special camera to create pictures of organ functions. Iodine 123 is currently used in evaluating and detecting disease in the thyroid gland.

The second research project is led by Robert de Kemp, PhD, Head Imaging Physicist, Cardiac Imaging, UOHI. This work involves Rubidium-82, a very short-lived tracer regarded as accurate and safer because it exposes patients to minimal radiation compared to conventional SPECT tracers labeled with Technetium-99m. Rubidium-82 can be produced at the Heart Institute in a small generator about the size of a miniature refrigerator and has been used on-site for more than 10 years in patients undergoing positron emission tomography (PET) scans to diagnose coronary artery disease.

"Our team of cardiologists, physicists, and nuclear medicine physicians at the Heart Institute will introduce the clinical use of this alternative medical isotope in several Canadian regions over the course of the next few months. Within two years, we expect to prove the utility and cost-effectiveness of this technology compared to Technetium-based tracers," said de Kemp.

Small amounts of radiological tracers are used in radiopharmaceuticals and medical isotopes. Once introduced, they light a pathway through the body as they are tracked by special cameras in SPECT and PET. While X-rays reveal organ structures inside the body, SPECT and PET produce two and three dimensional images to show physicians how the heart works, for example, and how blood flows in and through the heart muscle.

The Heart Institute conducts the largest volumes in Canada of cardiac imaging tests using a newly expanded suite of advanced imaging technologies. The Heart Institute also supplies the Ottawa area with alternative isotopes for imaging tests to diagnose cancer. This supply project is part of a national consortium of research organizations approved by Health Canada to produce medical isotopes for regional distribution. The reason: the Institute has its own cyclotron. A cyclotron produces short-lived, non-reactor medical isotopes by aiming a stream of accelerated protons at a target substance.