Bahadur Ali N, Giller Cole A, Kashyap Dheerendra, Liu Hanli
Children's Cancer Research Institute, University of Texas Health Science Center, San Antonio 78229, USA.
Appl Opt. 2007 Aug 10;46(23):5552-61. doi: 10.1364/ao.46.005552.
An optical probe used to localize human brain tissues in vivo has been reported previously. It was able to sense the underlying tissue structure with an optical interrogation field, termed as "look ahead distance" (LAD). A new side-firing probe has been designed with its optical window along its side. We have defined the optical interrogation field of the new side probe as "look aside distance" (LASD). The purpose of this study is to understand the dependence of the LAD and LASD on the optical properties of tissue, the light source intensity, and the integration time of the detector, using experimental and computational methods. The results show that a decrease in light intensity does decrease the LAD and LASD and that an increase in integration time of detection may not necessarily improve the depths of LAD and LASD. Furthermore, Monte Carlo simulation results suggest that the LAD/LASD decreases with an increase in reduced scattering coefficient to a point, after which the LAD/LASD remains constant. We expect that an optical interrogation field of a tip or side probe is approximately 1-2 mm in white matter and 2-3.5 mm in gray matter. These conclusions will help us optimally manipulate the parameter settings during surgery and determine the spatial resolution of the probe.
先前已有报道一种用于在体定位人类脑组织的光学探头。它能够通过一个被称为“前瞻距离”（LAD）的光学探测场感知其下方的组织结构。一种新的侧向发射探头已被设计出来，其光学窗口位于侧面。我们将这种新的侧向探头的光学探测场定义为“旁视距离”（LASD）。本研究的目的是使用实验和计算方法来了解LAD和LASD对组织光学特性、光源强度以及探测器积分时间的依赖性。结果表明，光强降低确实会减小LAD和LASD，而探测积分时间的增加不一定会提高LAD和LASD的深度。此外，蒙特卡罗模拟结果表明，LAD/LASD随着约化散射系数的增加而减小，直到某一点后，LAD/LASD保持恒定。我们预计，尖端或侧向探头的光学探测场在白质中约为1 - 2毫米，在灰质中约为2 - 3.5毫米。这些结论将有助于我们在手术过程中优化操作参数设置，并确定探头的空间分辨率。
