Experimental determination of photon propagation in highly absorbing and scattering media.
Experimental determination of photon propagation in highly absorbing and scattering media.
复制标题
DOI：
10.1364/josaa.22.000546
复制
发表时间：
2005-03
期刊：
影响因子：
--
通讯作者：
J. Ripoll;Doreen Yessayan;G. Zacharakis;V. Ntziachristos
中科院分区：
文献类型：
--
作者：
J. Ripoll;Doreen Yessayan;G. Zacharakis;V. Ntziachristos
组织中的光学成像和断层扫描可以促进几种重要发色团和荧光团的定量研究。多个理论模型已针对高散射和低吸收介质中的漫射光子传播进行了验证，这些模型描述了近红外 (NIR) 区域组织的光学外观。然而，这些模型通常不适用于可见光区域的定量光学研究，因为与近红外区域相比，该光谱区域的组织吸收明显更高。我们通过高度散射和吸收介质进行光子测量，测量吸收系数与减少的散射系数的比率，范围大约为 0 到 1。我们通过实验检验了 Aronson 和 Corngold 定义的吸收相关扩散系数的性能 [J.选择。苏克。是。 A 16, 1066 (1999)] 用于低吸收和高吸收区域中光子传播的定量估计。通过稳态测量，我们通过考虑对吸收具有非线性依赖性的修正扩散系数，验证了扩散方程可以很好地描述透射强度。这项研究证实，基于扩散近似的简单分析解决方案甚至适用于高吸收方案，并表明基于扩散近似的模型对于可见光组织的定量测量和断层成像是有效的。
Optical imaging and tomography in tissues can facilitate the quantitative study of several important chromophores and fluorophores. Several theoretical models have been validated for diffuse photon propagation in highly scattering and low-absorbing media that describe the optical appearance of tissues in the near-infrared (NIR) region. However, these models are not generally applicable to quantitative optical investigations in the visible because of the significantly higher tissue absorption in this spectral region compared with that in the NIR. We performed photon measurements through highly scattering and absorbing media for ratios of the absorption coefficient to the reduced scattering coefficient ranging approximately from zero to one. We examined experimentally the performance of the absorption-dependent diffusion coefficient defined by Aronson and Corngold [J. Opt. Soc. Am. A 16, 1066 (1999)] for quantitative estimations of photon propagation in the low- and high-absorption regimes. Through steady-state measurements we verified that the transmitted intensity is well described by the diffusion equation by considering a modified diffusion coefficient with a nonlinear dependence on the absorption. This study confirms that simple analytical solutions based on the diffusion approximation are suitable even for high-absorption regimes and shows that diffusion-approximation-based models are valid for quantitative measurements and tomographic imaging of tissues in the visible.