Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60208, USA.
J Biomed Opt. 2011 Jun;16(6):067007. doi: 10.1117/1.3589349.
Low-coherence enhanced backscattering (LEBS) is a depth selective technique that allows noninvasive characterization of turbid media such as biological tissue. LEBS provides a spectral measurement of the tissue reflectance distribution as a function of distance between incident and reflected ray pairs through the use of partial spatial coherence broadband illumination. We present LEBS as a new depth-selective technique to measure optical properties of tissue in situ. Because LEBS enables measurements of reflectance due to initial scattering events, LEBS is sensitive to the shape of the phase function in addition to the reduced scattering coefficient (μ(s) ()). We introduce a simulation of LEBS that implements a two parameter phase function based on the Whittle-Matérn refractive index correlation function model. We show that the LEBS enhancement factor (E) primarily depends on μ(s) (), the normalized spectral dependence of E (S(n)) depends on one of the two parameters of the phase function that also defines the functional type of the refractive index correlation function (m), and the LEBS peak width depends on both the anisotropy factor (g) and m. Three inverse models for calculating these optical properties are described and the calculations are validated with an experimental measurement from a tissue phantom.
低相干增强背向散射（LEBS）是一种深度选择技术，可用于非侵入式描述生物组织等混浊介质。LEBS 通过使用部分空间相干宽带照明，对入射和反射光线对之间的距离的组织反射分布进行光谱测量。我们提出了 LEBS 作为一种新的深度选择技术，用于原位测量组织的光学特性。由于 LEBS 能够测量初始散射事件引起的反射率，因此 LEBS 除了降低散射系数（μ(s) ()）之外，还对相函数的形状敏感。我们引入了一个基于 Whittle-Matérn 折射率相关函数模型的两参数相函数的 LEBS 模拟。我们表明，LEBS 增强因子（E）主要取决于 μ(s) ()，E 的归一化光谱依赖性（S(n)）取决于相函数的两个参数之一，该参数还定义了折射率相关函数的功能类型（m），而 LEBS 峰宽取决于各向异性因子（g）和 m。描述了三种用于计算这些光学特性的逆模型，并通过组织体模的实验测量对计算进行了验证。
