UBC researcher to develop medical isotope alternatives

(PhysOrg.com) -- A UBC Pharmaceutical Sciences researcher has been awarded $874,000 from the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council (NSERC) to develop alternatives to isotopes currently used in medical imaging.

UBC Asst. Prof. Urs Hafeli, an expert in drug delivery using biodegradable polymers, is principal investigator in two projects, each to be conducted over two years. The studies are part of a seven-project research program recently funded with $5.4 million from CIHR and NSERC. Called Alternative Radio-pharmaceuticals for Medical Imaging, the Canada-wide program will develop non-nuclear reactor technology alternatives to Technetium-99m (Tc-99m), an isotope commonly used in medical imaging procedures and currently in short supply worldwide.

The key to imaging procedures is the use of non-toxic radioactive markers, also called labels or tags, which are introduced into the blood stream. When the body is scanned with a radiation scanner, the tags can be detected and made into a three-dimensional image. Both funded projects use Gallium-68 (Ga-68), an isotope that can be created without a nuclear reactor and imaged with Positron Emission Tomography (PET).

Projects led by Hafeli are:

• Replacing a blood product called macroaggregated albumin that is tagged with Tc-99m with biodegradable microspheres tagged with Ga-68. The microspheres will be used in PET scans of lung perfusion, a diagnostic procedure that identifies pulmonary embolism, chronic obstructive pulmonary disease and lung cancer. The spheres are made from a biodegradable polymer which removes risk of viral contamination posed by albumin. In addition, the microspheres can be uniformly sized to “clog” the lung’s smallest blood vessels. This limits the distribution of microspheres in the body, eliminates any risk of toxic effect, and maximizes imaging quality. Dr. Francois Bénard of the BC Cancer Agency is a collaborator on the study.

• Replacing red blood cells tagged with Tc-99m with a biocompatible polymer tagged with Ga-68 for cardiac blood pooling imaging that determines healthy heart function. The new method will simplify the procedure and eliminate handling of blood and blood components. Using a biocompatible polymer also removes risk of adverse interaction between isotopes and chemotherapeutic drugs. Bénard and Prof. Don Brooks of UBC’s Dept. of Pathology and Laboratory Medicine are collaborators on the study.

Researchers will have completed preliminary imaging studies in clinical trials within two years.

Provided by UBC