Grant: Discovery Grants Program - Individual

This proposal introduces and outlines new research directions for X-ray spectrometry in the investigation of trace elements within tissue samples. This will ultimately help provide improved biomarkers for understanding the distribution of elements of interest, such as zinc, in the human body. The program of research for the coming five-year period will concentrate on the development and evaluation of X-ray fluorescence techniques for the detection of zinc in fingernail, toenail, and hair samples. Experimental equipment will include a mono-energetic portable X-ray fluorescence system along with a variety of other measurement techniques available through an array of collaborations. Previous work has introduced normalization techniques to allow results from portable X-ray spectrometry to provide elemental concentrations. In this proposal, improvements to the analysis of X-ray energy spectra will be explored. Results will be compared against concentrations obtained from well-established methods such as inductively coupled plasma mass spectrometry. Work will initially involve analysis of nail clippings drawn from international studies having a particular focus on zinc intake. With a stronger understanding of spectral analysis established, attention will extend to the assessment of zinc content within hair. A single strand of hair may have the ability to unlock crucial time-dependent information on zinc intake. Portable X-ray spectrometry will be used to map zinc as a function of position along the hair and therefore as a function of time. This line of research will investigate hair from grizzly bears having a well-studied diet, with a focus on the ability to accurately measure zinc concentration over a series of spatial steps. Recent improvements in spatial resolution in lab-based micro X-ray fluorescence (µXRF) will be examined, with applications to both nail clipping and hair analysis. The capabilities of a lab-based µXRF system will be compared with new results obtained from synchrotron measurements at the Canadian Light Source. Results from these two high-resolution and highly sensitive methods will in turn help inform an optimized approach to the measurement of zinc and other trace elements using smaller-scale, portable, X-ray fluorescence. This program of research makes use of ionizing radiation and involves the physics of photon interactions with matter. These themes align the subject material closely to medical physics and radiation physics. The development of a fast, precise, and portable system for reliably assessing zinc concentration in tissue samples would be important. If successful, this research program would contribute toward worldwide zinc fortification efforts and therefore have a high impact on society.