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首页> 外文学位 >Spatial localization and temporal analysis of optical property fluctuations by multiplexed near-infrared photon density waves in turbid media: In vitro and in vivo studies.
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Spatial localization and temporal analysis of optical property fluctuations by multiplexed near-infrared photon density waves in turbid media: In vitro and in vivo studies.

机译：在混浊介质中通过多路近红外光子密度波进行光学特性波动的空间定位和时间分析：体外和体内研究。

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摘要

In recent years the application of near infrared non-invasive methods for medical diagnostics and clinical studies has grown rapidly. The ease of use, low cost and portability of these methods is a clear advantage over other techniques such as MRI. The limitations in detection of optical property inhomogeneities in tissues, such as tumors or hematomas, is due to the diffusive, highly scattering nature of near infrared light propagation. I have studied and developed methods to improve the spatial localization of these inhomogeneities in biological tissues, especially for the application of functional studies of the human brain in vivo.; Recently much attention has been given to the study of the processes in the human brain that lead to the changing of the optical parameters that characterize the tissue, measured by our frequency-domain instrumentation. These processes have been divided into two main categories with different time-scales. The slower one is mostly due to the fluctuations in the absorption coefficient caused by oxy- and deoxy-hemoglobin changes in the tissue. The temporal analysis of the signal resulting from this process is studied in detail, and I also introduce a time-series data analysis technique that has not been applied to this field before but was introduced in another area very recently. The faster time-scale process has been attributed to the electrochemical excitation of the individual neurons in the brain that have been observed to cause a change in the scattering coefficient of the tissue. This is the other primary parameter that is measured by our frequency domain instrument. However, before this work it has not been clear how to go about to better localize these smaller fluctuations. I present a novel idea for improving spatial localization of macroscopic optical parameter fluctuations, and study the characteristics of this optical probe design using analytical solutions to the diffusion equation and Monte Carlo simulations that more appropriately represent the volume of excitation of the cortex neurons.
机译：近年来，近红外非侵入性方法在医学诊断和临床研究中的应用迅速增长。与其他技术（例如MRI）相比，这些方法的易用性，低成本和可移植性是其明显的优势。检测诸如肿瘤或血肿等组织的光学特性不均匀性的局限性是由于近红外光传播具有扩散性，高散射性。我已经研究和开发了改善这些不均匀性在生物组织中的空间定位的方法，尤其是在人脑的体内功能研究中的应用。最近，人们对人脑过程的研究给予了极大关注，这些过程导致通过组织的频域仪器测量的表征组织的光学参数发生变化。这些过程已分为具有不同时标的两个主要类别。一个较慢的原因主要是由于组织中氧合和脱氧血红蛋白的变化引起的吸收系数的波动。对由该过程产生的信号的时间分析进行了详细研究，并且我还介绍了一种时序数据分析技术，该技术以前尚未应用于该领域，但最近已在另一领域引入。更快的时标过程归因于大脑中各个神经元的电化学激发，已观察到它们会引起组织散射系数的变化。这是我们的频域仪器测量的另一个主要参数。但是，在进行这项工作之前，尚不清楚如何更好地定位这些较小的波动。我提出了一种改善宏观光学参数波动的空间定位的新思路，并使用扩散方程的解析解和蒙特卡罗模拟研究了这种光学探针设计的特征，这些解析方程更能代表皮层神经元的激发量。

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  • 作者

    Filiaci, Mattia Emidio.;

  • 作者单位

    University of Illinois at Urbana-Champaign.;

  • 授予单位 University of Illinois at Urbana-Champaign.;
  • 学科 Biophysics Medical.; Physics Optics.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 103 p.
  • 总页数 103
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生物物理学;光学;
  • 关键词

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