Dr. Michael Wieser

• Applications of Isotopes as Environmental Tracers
• High Accuracy Measurement of Isotope Abundance and Atomic Weight
• Thermal Ionization and Multiple Collector Inductively Coupled Mass Spectrometry
• Experimental Methods in Physics
• Modern and Nuclear Physics
• Investigating the pathways and processes of trace metals in the geosphere and biosphere
• Precision measurement with isotopic tools

My research objective is to explore the interactions of metals in living and non-living systems by studying changes in the isotopic compositions of biochemically significant elements. Subtle but significant variations in the isotopic compositions of such elements are often clues to the processes that affect the biogeochemical cycling of the atoms. I am working towards developing an understanding of the significance of these elements at the interface between the geosphere and biosphere through the development and application of insightful and reliable mass spectrometric analytical tools.

I am a member of TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) collaboration at the TRIUMF particle accelerator in Vancouver, BC. The TITAN facility is a platform for research into the physics of exotic nuclei, with applications in nuclear physics, astrophysics, and laser spectroscopy. As a member of the collaboration, I contribute my knowledge of metrology, ion sources, and methods and applications of precision isotope abundance studies. At present, one significant activity is the development of a laser-based ion source that can be interfaced to the mass analyzer that will enable high spatial resolution of organic and inorganic materials. While still at a very early stage, the goal of this technology is to enable unparalleled sensitivity in the identification of specific isotopes and will open new frontiers of research and investigation in the health sciences.

I work with the Commission on Isotopic Abundances and Atomic Weights, a standing committee under the auspices of the International Union of Pure and Applied Chemistry. This Commission, under the International Union of Pure and Applied Chemistry, is the world’s oldest continuously serving scientific body. Established in 1899, the Commission is comprised of the world’s leading experts on isotopic abundance measurements and is responsible for the evaluation and dissemination of atomic weight and isotope abundance data for use in scientific research, education, and industry.

I began my career as a tenured faculty member at the University of Calgary in 1999 where, with my research group, I operate a mass spectrometry facility and clean room laboratory.

Radon Exposure and Cancer Risk

The goal of our research is to establish a reliable quantitative biodosimeter to monitor the accumulation of radioactive decay products in humans that are from the exposure to 222Rn gas in the home and work environments. An understanding of an individual’s radon exposure is critical in defining a personal cancer risk. At present, the available methods can only quantify the current radon exposure levels and there are very limited methods to assess the radon levels for all homes, workplaces and schools that a person may have occupied through their lifetime. Only estimates for regions or larger areas may be available and cancer risk estimates are restricted to population levels. We are working towards a method to measure the amounts of the radioactive decay products from 222Rn that have accumulated in biological tissues in an effort to link individual cancers to radon, establish patterns of individual genetic susceptibility to radon-induced cancer risk and fully understand the scope of radon-induced disease without having to rely on extrapolation or modelling. Radon nuclei emit alpha particles in the lungs of people exposed to the environment and the atoms decay eventually to 210Pb and 210Po, two daughter products that are absorbed in bone, soft tissues (including lungs) and keratinizing tissues (including hair and nails). We are developing state-of-the-art analytical methods to quantify the amounts of these radioactive elements using isotope dilution mass spectrometry supported by a metal-free laboratory and isotope ratio mass spectrometry. This approach would be a significant improvement in more conventional counting methods in terms of the sensitivity and turn-around times. Further, the application of isotope ratio mass spectrometry to a range of biosamples would enable us to establish an individual’s historic radon exposure as the bioaccumulation of 210Pb, with its relatively long half-life, will be readily detectable for decades following exposure.