Indian Institute of Science, Department of Physics, Bangalore, India.
J Biomed Opt. 2013 Feb;18(2):26023. doi: 10.1117/1.JBO.18.2.026023.
The solution of the forward equation that models the transport of light through a highly scattering tissue material in diffuse optical tomography (DOT) using the finite element method gives flux density (Φ) at the nodal points of the mesh. The experimentally measured flux (Umeasured) on the boundary over a finite surface area in a DOT system has to be corrected to account for the system transfer functions (R) of various building blocks of the measurement system. We present two methods to compensate for the perturbations caused by R and estimate true flux density (Φ) from Umeasuredcal. In the first approach, the measurement data with a homogeneous phantom (Umeasuredhomo) is used to calibrate the measurement system. The second scheme estimates the homogeneous phantom measurement using only the measurement from a heterogeneous phantom, thereby eliminating the necessity of a homogeneous phantom. This is done by statistically averaging the data (Umeasuredhetero) and redistributing it to the corresponding detector positions. The experiments carried out on tissue mimicking phantom with single and multiple inhomogeneities, human hand, and a pork tissue phantom demonstrate the robustness of the approach.
正问题的解通过有限元方法模拟了漫射光学断层扫描（DOT）中光通过高度散射组织材料的传输，给出了网格节点处的通量密度（Φ）。在 DOT 系统中，有限表面区域上边界的实验测量通量（Umeasured）必须经过修正，以考虑测量系统各个组成部分的系统传递函数（R）。我们提出了两种方法来补偿 R 引起的扰动，并从 Umeasuredcal 中估计真实的通量密度（Φ）。在第一种方法中，使用均匀体模的测量数据（Umeasuredhomo）来校准测量系统。第二种方案仅使用来自非均匀体模的测量来估计均匀体模的测量，从而消除了对均匀体模的需求。这是通过对数据（Umeasuredhetero）进行统计平均并将其重新分配到相应的探测器位置来完成的。在具有单个和多个不均匀性的组织模拟体模、人手和猪肉组织体模上进行的实验证明了该方法的稳健性。
