Instrumental Analysis

仪器分析

• 批准号: 7966713
• 负责人: George H Weiss
• 金额: $ 9.65万
• 依托单位: CENTER FOR INFORMATION TECHNOLOGY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7966713
• 关键词: Accounting; Affect; Animal Model; Anisotropy; Bypass; Cancer Diagnostics; Cells; Cellular Structures; Collaborations; Data; Development; Diffusion; Fiber; Fluorescence; Goals; Image; Imaging Techniques; Infrared Rays; Investigation; Ionizing radiation; Literature; Measurement; Measures; Modeling; National Institute of Child Health and Human Development; Optics; Penetration; Photons; Publishing; Research; Techniques; Therapeutic; Time; Tissues; Transillumination; Translating; Walking; Work; absorption; base; design; fluorophore; member; optical imaging; physical property; research study; theories

Two main topics constituted the main thrust of the optical imaging project. Because photons suffer significant scattering by cell components it is necessary to determine physical properties of photon trajectories in terms of some form of diffusion, random walk, or transport theory. Up till about the year 2000 the standard assumption was that optical tissue parameters were isotropic with respect to cell geometry. Since that time it has become more and more evident that this assumption is violated in a significant number of measurements. For example, photons tend to move preferentially along fibers. This phenomenon has stimulated our research on the effects of optical parameter anisotropy on techniques used to detect differences between normal and abnormal tissues as well as to estimate the amount of tissue interrogated by photons involved in optical measurements. A mathematical formalism, based on random walk theory, originally developed by members of MSCL to incorporate optical anisotropy has been used to produce a simple measure of the degree to which contrast due to the presence of an abnormal inclusion in a tissue is affected by the presence of optical anisotropy. A further project along these lines is that of determining how anisotropic optical parameters affects the amount of penetration of photons into a tissue as a measure of how much of the tissue is investigated in different types of imaging experiments. A presently popular technique in optical imaging related to cancer diagnostics and related animal models is based on fluorophore-conjugated probes. We have recently developed a model based on the continuous-time lattice random walk which considerably extends previous theoretical work on fluorescence lifetime imaging by removing rather severe restrictions imposed on the basic theoretical formalism previously described in the literature. Prior theory appears to be valid for fluorophore parameters that differ by two orders of magnitude from those measured in NICHD experiments. The theory developed by members of MSCL take this difference into account, as well as the absorption coefficient with results that differ significantly from the earlier published work on this subject. Work is continuing both on the theoretical development and on numerical techniques for estimating parameters necessary to translate experimental data into useable information. More recently we have begun an investigation of the effects of anisotropic optical coefficients on transillumination measurements in collaboration with members of NICHD. The basic results have been established and are presently being checked and extended.

两个主要主题构成了光学成像项目的主旨。由于光子受到细胞成分的显著散射，因此有必要根据某种形式的扩散、随机游走或传输理论来确定光子轨迹的物理性质。直到2000年左右，标准的假设是光学组织参数相对于细胞几何形状是各向同性的。从那时起，越来越明显的是，这一假设在大量的测量中被违反了。例如，光子倾向于优先沿纤维运动。这一现象刺激了我们对光学参数各向异性对用于检测正常和异常组织之间的差异以及估计光学测量中涉及的光子所询问的组织数量的技术的影响的研究。最初由MSCL成员开发以结合光学各向异性的基于随机游走理论的数学形式已被用于产生由于组织中存在异常包裹体而导致的对比度受光学各向异性的存在影响的程度的简单测量。沿着这些思路的另一个项目是确定各向异性光学参数如何影响光子对组织的穿透量，以此来衡量在不同类型的成像实验中研究了多少组织。 目前，在与癌症诊断和相关动物模型相关的光学成像中，一种流行的技术是基于荧光团标记的探针。我们最近发展了一个基于连续时间晶格随机游走的模型，通过消除对文献中描述的基本理论形式的相当严格的限制，大大扩展了先前关于荧光寿命成像的理论工作。先前的理论似乎适用于与NICHD实验中测量的荧光参数相差两个数量级的荧光团参数。MSCL成员开发的理论考虑了这种差异，以及吸收系数，结果与早先发表的关于这一主题的工作有很大不同。在理论发展和估计将实验数据转化为有用信息所需参数的数值技术方面的工作仍在继续。 最近，我们与NICHD成员合作，开始研究各向异性光学系数对透光测量的影响。基本成果已经确定，目前正在检查和推广。