Grant: Discovery Grants Program - Individual

This program is aimed at developing a novel spectroscopic system and associated quantification methodology for performing X-ray fluorescence spectrometry--based elemental quantification in complex samples, in vivo/in situ, whereby inhomogeneity must be acknowledged and incorporated into the measurement and calibration process. This approach being applicable to various scenarios whereby this program is using the in vivo bone metal quantification process given its overarching complexity and direct and current societal need. Specifically, this program will evaluate and develop solutions to the said problem for the quantification of strontium in vivo given current need to measure strontium in bone reliably to improve bone density measurements in supplemented individuals as well as for the study of strontium's potential essentiality to bone health in humans. This program is aimed at designing a new X--ray tube--based spectroscopic system which is to acquire X-ray fluorescence spectrometry data as a computed tomography set over various measurement angles and over various slices at the measurement site. This being achievable given the already established negligible radiation dose individuals receive from these in vivo bone measurements. The approach to be developed and evaluated is to combine the use of imaging data (i.e. CT data) of the measurement site to produce an image set with voxels containing reliable data on the gross composition of the sample matrix at the measurement site. This data is then be used to perform a novel iterative inverse Monte Carlo quantification procedure based on the acquired and combined set of data to provide an estimate of the elemental concentration/distribution within the sample measurement site. This approach presents various challenges, to be evaluated in this program, which are applicable to other areas of interest (i.e. cultural heritage applications): 1) The acquired X-ray fluorescence data is based on a photon emission process rather than X--ray transmission process, as in conventional X--ray computed tomography imaging. Given that the analytical signal is in the soft X--ray range (<40 keV), and, that the sample of interest has a rather large attenuation coefficient, one of the main challenges to be addressed in this program is the issue of image and elemental concentration distribution reconstruction with significantly truncated data sets. 2) The imaging system to be used requires evaluation and development in terms of producing reliable data for the Monte Carlo--based quantification including the need to develop reliable phantoms for the said application. 3) A full novel multivariate calibration regime needs to be developed.