Elemental analysis in medical physics and astro-geology

拟议研究计划的中心主题是将辐射物理应用于医学物理和天文地质学中的元素分析。该计划由三个主要举措组成：1)测量火星土壤样本中的结合水美国宇航局2004/2006年任务期间搭载的火星探测车上的阿尔法粒子X射线光谱仪(APXS)提供了大量火星岩石和土壤样本的元素分析。*有一些迹象表明，这些样本中含有大量水体蒸发后留下的盐分，APXS的高级版本将在2009/2010年间部署，以进一步研究这一假设。这个研究项目将根据APXS光谱中观察到的散射特征来调查间接检测火星样品中轻元素的敏感性。2)用X射线荧光测量银在许多情况下都可能发生职业接触银。此外，在替代医学中推广的银化合物的医疗用途重新出现。这样的暴露可能会导致不良的生物影响，如银色，一种永久性的皮肤变色。这项工作将研究体内非侵入性技术的应用，以检测有患银质症风险的人皮肤中的银，目的是在这种不可逆转的皮肤状况开始之前提供一种干预手段。3)用伽马射线共振吸收法测量氮的能力测量氮的能力是评估许多营养紊乱中蛋白质状态的直接手段。这项研究的目标是探索一种替代现有方法的方法，该方法存在问题。这种新的测量技术有可能大幅提高当前方法的一致性和剂量，并将促进一些与医学和健康相关的领域的临床研究，例如营养科学、儿科、老年学、运动学和康复科学。

The central theme of the proposed research program is the application of radiation physics to elemental analysis in medical physics and astro-geology.  The program consists of three major initiatives:1) Measuring Bound Water in Martian Soil SamplesThe alpha-particle x-ray spectrometers (APXS) carried on the Mars Exploration Rovers during NASA's 2004/2006 mission have provided elemental analysis of a large number of Martian rock and soil samples.  There are some suggestions that these samples contain salts left behind after the evaporation of large bodies of water, and an advanced version of APXS will be deployed in 2009/2010 to further investigate this hypothesis.  This research project will investigate the sensitivity of indirect detection of light elements in Martian samples based on the observed scatter features present in the APXS spectra.2)Measuring Silver with X-ray FluorescenceOccupational exposure to silver can occur in many settings.  Furthermore, there has been a re-emergence of the medicinal use of silver compounds, promoted in alternative medicine. Such exposure can lead to adverse biological effects such as argyria, a permanent skin discoloration. This work will investigate the application of a non-invasive in vivo technique to detect silver in the skin of individuals who are at risk of developing argyria, with the aim of providing a means of intervening before the onset of this irreversible skin condition.3) Measuring Nitrogen with Gamma-ray Resonance AbsorptionThe ability to measure nitrogen is a direct means of assessing protein status in many nutritional disorders. The goal of this research is to investigate an alternative approach to the current method, which is problematic.  This new measurement technique has the potential to improve substantially the uniformity and dose of the current method, and would facilitate clinical studies in a number of medical and health-related fields, e.g. nutritional sciences, pediatrics, gerontology, kinesiology and rehabilitation sciences.