Liebert A, Zołek N, Maniewski R
Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland.
Phys Med Biol. 2006 Nov 21;51(22):5737-51. doi: 10.1088/0031-9155/51/22/002. Epub 2006 Oct 19.
A method for measurement of distribution of speed of particles moving in an optically turbid medium is presented. The technique is based on decomposition of the laser-Doppler spectrum. The theoretical background is shown together with the results of Monte Carlo simulations, which were performed to validate the proposed method. The laser-Doppler spectra were obtained by Monte Carlo simulations for assumed uniform and Gaussian speed distributions of particles moving in the turbid medium. The Doppler shift probability distributions were calculated by Monte Carlo simulations for several anisotropy factors of the medium, assuming the Hanyey-Greenstein phase function. The results of the spectra decomposition show that the calculated speed distribution of moving particles match well the distribution assumed for Monte Carlo simulations. This result was obtained for the spectra simulated in optical conditions, in which the photon is scattered with the Doppler shift not more than once during its travel between the source and detector. Influence of multiple scattering of the photon is analysed and a perspective of spectrum decomposition under such conditions is considered. Potential applications and limitations of the method are discussed.
本文提出了一种测量在光学浑浊介质中运动的粒子速度分布的方法。该技术基于激光多普勒光谱的分解。给出了理论背景以及蒙特卡罗模拟结果，进行这些模拟是为了验证所提出的方法。通过蒙特卡罗模拟获得了激光多普勒光谱，这些模拟针对在浑浊介质中运动的粒子假定的均匀和高斯速度分布。在假设哈尼耶 - 格林斯坦相位函数的情况下，通过蒙特卡罗模拟计算了介质几个各向异性因子的多普勒频移概率分布。光谱分解结果表明，计算得到的运动粒子速度分布与蒙特卡罗模拟所假定的分布匹配良好。这个结果是针对在光学条件下模拟的光谱得到的，在这种条件下，光子在源和探测器之间传播过程中散射时多普勒频移不超过一次。分析了光子多次散射的影响，并考虑了在这种条件下光谱分解的前景。讨论了该方法的潜在应用和局限性。
