New directions for x-ray spectrometry from portable to synchrotron science

这项提议寻求开发和使用新的X射线光谱分析方法来检测人体组织中的微量元素。科学的规模从便携式、台式、X射线仪器到大规模的同步加速器设施。该提案侧重于X射线荧光和X射线吸收，以研究包括锌、砷和硒在内的一系列元素。与其他小组的合作将允许使用其他不同的分析方法。正在考虑的样本将包括组织模拟材料和真实组织，如指甲和脚趾甲。该提案的三个相互关联的目标是：(1)开发创新和便携式单能X射线荧光技术；(2)便携式X射线荧光与其他新兴科学方法的比较；(3)利用加拿大光源的同步辐射调查组织中微量元素之间的关系。微型X射线管和X射线光学的最新发展首次使单能便携式X射线荧光用于组织研究成为可能。一个单能量的光束，调谐到一个有利的能量，将大大超过以前使用一系列能量的方法。当试图检测组织中的微量元素时，这一点很重要。还将研究新的数据分析方法，以评估人造和真实指甲剪下的元素。并将结果与激光烧蚀电感耦合等离子体质谱、激光诱导击穿光谱、微量x射线荧光等方法进行比较。同步辐射时间将被用来研究指甲碎片中元素的分布和化学形态。将寻找指甲中存在砷和硒的特定结合物的证据。*使用电离辐射探测组织是这项研究计划的核心，该计划属于医学物理和辐射物理领域。展示一种快速、准确和便携的系统来可靠地评估指甲剪下的锌含量将是一项重大发展，可能会促进全球锌的补充工作。同样，有耐人寻味的证据表明，摄入硒可能会抵消砷暴露的影响。因此，评估砷和硒水平的方法很重要，更好地了解砷和硒之间的结合机制是至关重要的。为了考虑这些问题，拟议的研究包括从基础科学到辐射物理的实际应用的方方面面。********

This proposal seeks to develop and use new x-ray spectrometry approaches for the detection of trace elements in human tissue. The scale of the science ranges from portable, desktop, x-ray instruments to large-scale synchrotron facilities. The proposal focuses on x-ray fluorescence and x-ray absorption for the study of a series of elements including zinc, arsenic, and selenium. Collaboration with other groups will allow the use of additional and different methods of analysis. Samples under consideration will include tissue-simulating materials and real tissue such as fingernails and toenails. Three inter-related objectives of the proposal are: (1) development of an innovative and portable mono-energetic x-ray fluorescence technique; (2) comparison of portable x-ray fluorescence with other emerging scientific methods; and (3) investigation of the relationships between trace elements in tissue using synchrotron radiation at the Canadian Light Source. ******Recent developments in miniature x-ray tubes and x-ray optics have for the first time made mono-energetic portable x-ray fluorescence feasible for tissue studies. A mono-energetic beam, tuned to a favorable energy, will vastly outperform previous methods which use a range of energies. This is important when trying to detect trace elements in tissue. New approaches to data analysis will also be studied for the assessment of elements in artificial and real nail clippings. Results will be compared and contrasted with those from other methods including laser ablation inductively coupled plasma mass spectrometry, laser induced breakdown spectroscopy, and micro x-ray fluorescence. Synchrotron beam time will be used to investigate the distribution and chemical form of elements in nail clippings. Evidence will be sought for the presence of a specific conjugate of arsenic and selenium within nail. ******The use of ionizing radiation for probing tissue is central to this program of research, which falls within the fields of medical physics and radiation physics. The demonstration of a fast, precise, and portable system for reliably assessing levels of zinc in nail clippings would be a significant development which could facilitate worldwide zinc supplementation efforts. Likewise, there has been intriguing evidence that the effects of arsenic exposure may be counteracted by intake of selenium. A means of assessing both arsenic and selenium levels is therefore important, and a better understanding of the mechanism of binding between arsenic and selenium is critical. To consider such issues, the proposed research incorporates aspects ranging from basic science to practical applications of radiation physics. ********