Ex vivo analysis of irradiated finger and toe nails as a biodosimeter system Fla

达特茅斯大学U19 CMCR项目的目标是开发基于离体和体内电子顺磁共振（EPR）光谱法测量手指/脚趾指甲（“指甲”）或牙齿中辐射诱导信号（RIS）的现场生物剂量测定技术。在本项目(2)中，进一步发展了用于测量钉子的离体EPR方法，以实现现场可部署应用。为了实现这一目标，我们制定了四个目标，分别是信号表征、样本处理和信号反卷积以去除干扰信号、测试方法的验证、可能影响RIS信号变异性的因素的识别和表征，以及建立适合非专业操作人员和ER管理人员在现场条件下使用的数据采集、处理和输出方法。对未辐照和辐照指甲中EPR信号的总体特征、光谱成分和分子基础进行系统的研究是很重要的

The objectives ofthe Dartmouth University U19 CMCR program are to develop field biodosimetry techniques that are based on ex vivo and in vivo electron paramagnetic resonance (EPR) spectrometry measurements of a radiation-induced signal (RIS) in finger/toe nails ("nails") or teeth. In this project (2), the ex vivo EPR method for measuring nails is further developed towards a field deployable application. To achieve this goal, four objectives have been deflned that address signal characterization, sample treatment and signal deconvolution to remove interfering signals, validation of test methods, identification and characterization of factors that have the potential to impact the variability of the RIS signal, and establish methods for data acquisition, processing and output suitable for use by non-expert operators and ER managers under field conditions. Characterization ofthe overall signal, the spectral components and pursuing a systematic investigation of the molecular basis of the EPR signals in both unirradiated and irradiated nails is important towards developing approaches for separating the radiation-induced signal from a mechanically-induced signal (MIS). Some aspects of these studies will utilize the data from Project 3, which will provide EPR spectra of nails without clipping, and therefore help to differentiate more clearly the origin and nature of the signals from the clipping process. The result of this set of studies is the development of a basis set of spectral components ofthe RIS an MIS signals, coupled with the decay kinetics ofthe separate component signals that are integrated into a spectrum deconvolution procedure for extracting the RIS component signal. Variability in RIS and MIS signals are to be characterized with respect to nail water content, demographics (i.e. age, race), systemic variables (pregnancy, diet/supplements, nail disorders) and fungal infection. Finally, delineating a field-usable method for sample procurement, placement ofthe samples into the spectrometer, the analytic software to determine the dose, and delineation of factors that if present need to be considered in the calibration of the results. While the construction of a field-deployable prototype that meets the overall goals ofthe Center will be carried out in collaboration with the instrumental core at Dartmouth, this project will develop the methodology to be implemented in the development and construction.