新型门控光子计数法测量高散射介质的光学参量

Recovery of Optical Parameters in Diffusive Media with a New Gated Photon Counting Method

讨论了一种新型而且简单的门控光子计数法 ,用来测量高散射介质的光学参量。当一束光脉冲入射到高散射介质后 ,该方法可以恢复出光脉冲经过散射后从介质表面逸出的波形。与传统的门控光子计数法相比 ,该方法利用计数器控制门可以移动的特点 ,通过滑动宽度为 6 0ns的控制门实现较高的时间分辨力 2 0 0 ps。在此波形的基础上 ,Patterson Chance方法可以快速而且准确计算出被测介质的光学参量。在模型介质上的实验 ,验证了该方法的可行性 ,实验结果与复杂的时间相关的单光子计数加曲线拟合方法相比较 ,误差小于 10 %。

A new and simple gated photon counting system is described for the recovery of optical parameters in diffusive media. Compared with the traditional gated photon counting technique, the system is based on a 60 ns width-sliding gate that enables reconstruction of the photon decay curve at 200 ps time resolution, which is detected when a light pulse is impinged on the diffusive media. Patterson-Chance method allows the optical parameters of the medium under investigation to be retrieved quickly and accurately. Experimental results on a phantom modeling breast tissue demonstrate the feasibility of the technique. Good agreement with complicated time-correlated single photon counting technique plus curve-fitting method was achieved leading to less than 10% of miss-estimation on the optical parameters.