生物组织折射率的概念界定与测试方法研究

【作者】 徐乃洲；

【导师】 李振华；

【作者基本信息】 南京理工大学 ， 生物医学工程， 2004， 硕士

【摘要】 随着组织光学研究的深入，唯像模型的基本参数己不再能满足描述生物组织光学特性的要求，这促使我们去寻找一种更加基本的物理量来描述生物组织的光学特性。基于此考虑，本文从光的电磁理论出发，结合生物组织的光学特性界定生物组织折射率为一个复数，它可以作为描述组织光学特性的独立参数，并可将唯像模型的基本参数统一于此独立参数。在此基础上，引入相衬显微术对生物组织切片内的折射率分布进行半定量的测量，并讨论了复折射率和切片厚度对相衬成像特性的影响，给出了典型的测量结果。阐明了唯像模型中所用折射率值的具体含义，在处理组织边界问题时应为等效折射率，而平均折射率则用以表征时间分辨模型中光的传播速度，两者有所区别；同时改进了生物组织折射率的全反射测量方法，发展了一种生物组织等效折射率的确定算法，对几种典型的组织样品进行了定量测量。探讨了椭圆偏振测量术应用生物组织复折射率测量的可行性，建立了相应的实验装置并进行了初步的实验测量。此外，论文最后还讨论了会聚光在半无限生物组织内的传输问题。更多还原

【Abstract】 With in-depth research of tissue optics, basic optical parameters in radiative transfer theory can’t fulfill the demands of depicting optical characteristics of biological tissues, which impel us to search for a fundamental parameter. Combine the electromagnetism theory of optics with optical characteristics of biological tissues, we define that refractive index of tissues is a complex number which can serve as a fundamental parameter and unify the optical parameters of tissues. We observe some kinds of typical tissue slices under the phase contrast microscope and analyze the influence of refractive index and thickness of slices on the contrast of phase contrast micrographs, additionally distribution of refractive index is deduced from the phase contrast micrographs. We illuminate the specific meaning of refractive index which serves as equivalent refractive index when dealt with boundary problem and average refractive index used in time-resolved model to describe the velocity of light. A new algorithm is put forward to calculate the equivalent refractive index and some kinds of biological tissues are quantificationally measured in experiment. Feasibility of measuring complex refractive index with ellipsometry is discussed and a set of experiment equipment is set up to make elementary experiment. In the last chapter of this paper, the influence of convergence angle on the light field in biological tissues and light field reflected from biological tissues are also discussed.更多还原