The effects of internal refractive index variation in near-infrared optical tomography: a finite element modelling approach
The effects of internal refractive index variation in near-infrared optical tomography: a finite element modelling approach
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DOI：
10.1088/0031-9155/48/16/310
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发表时间：
2003-08-21
影响因子：
3.5
通讯作者：
Paulsen, KD
中科院分区：
文献类型：
--
作者：
Dehghani, H;Brooksby, B;Paulsen, KD
近红外（NIR）断层扫描是一种用于测量通过组织的光传播并从边界测量生成内部光学特性分布图像的技术。最流行的应用集中在女性乳房成像，新生儿和成人头部成像，以及肌肉和小动物研究。在大多数情况下，假设在整个成像域中具有均匀折射率的高度散射介质。使用这些假设，可以将模型简化为扩散近似。然而，生物组织包含变化的光学吸收和散射以及变化的折射率的区域。在这项工作中，我们引入了一个内部边界约束的有限元方法来模拟光通过组织的传播，占不同的折射率的区域。我们已经比较的结果，从Monte Carlo模拟的数据，并表明，对于一个简单的两层板模型的不同的折射率，测量的反射率数据的相位显着改变的内部折射率的变化，而振幅数据只受到轻微的影响。
Near-infrared (NIR) tomography is a technique used to measure light propagation through tissue and generate images of internal optical property distributions from boundary measurements. Most popular applications have concentrated on female breast imaging, neonatal and adult head imaging, as well as muscle and small animal studies. In most instances a highly scattering medium with a homogeneous refractive index is assumed throughout the imaging domain. Using these assumptions, it is possible to simplify the model to the diffusion approximation. However, biological tissue contains regions of varying optical absorption and scatter, as well as varying refractive index. In this work, we introduce an internal boundary constraint in the finite element method approach to modelling light propagation through tissue that accounts for regions of different refractive indices. We have compared the results to data from a Monte Carlo simulation and show that for a simple two-layered slab model of varying refractive index, the phase of the measured reflectance data is significantly altered by the variation in internal refractive index, whereas the amplitude data are affected only slightly.