Shizuoka University, Faculty of Engineering, Department of Electrical and Electronic Engineering, Ha, Japan.
J Biomed Opt. 2018 Mar;23(3):1-4. doi: 10.1117/1.JBO.23.3.030503.
We quantitatively investigated the measurement sensitivity of spatially resolved spectroscopy (SRS) across six tissue models: cerebral tissue, a small animal brain, the forehead of a fetus, an adult brain, forearm muscle, and thigh muscle. The optical path length in the voxel of the model was analyzed using Monte Carlo simulations. It was found that the measurement sensitivity can be represented as the product of the change in the absorption coefficient and the difference in optical path length in two states with different source-detector distances. The results clarified the sensitivity ratio between the surface layer and the deep layer at each source-detector distance for each model and identified changes in the deep measurement area when one of the detectors was close to the light source. A comparison was made with the results from continuous-wave spectroscopy. The study also identified measurement challenges that arise when the surface layer is inhomogeneous. Findings on the measurement sensitivity of SRS at each voxel and in each layer can support the correct interpretation of measured values when near-infrared oximetry or functional near-infrared spectroscopy is used to investigate different tissue structures.
我们定量研究了空间分辨光谱（SRS）在六种组织模型中的测量灵敏度：脑组织、小动物脑、胎儿前额、成人脑、前臂肌肉和大腿肌肉。使用蒙特卡罗模拟分析了模型体素中的光程。结果表明，测量灵敏度可以表示为吸收系数变化与不同源-探测器距离下两个状态的光程差的乘积。结果阐明了每个模型在每个源-探测器距离处的表面层和深层之间的灵敏度比，并确定了当一个探测器靠近光源时深层测量区域的变化。与连续波光谱的结果进行了比较。该研究还确定了当表层不均匀时出现的测量挑战。在使用近红外血氧仪或功能近红外光谱研究不同组织结构时，每个体素和每个层的 SRS 测量灵敏度的研究结果可以支持对测量值的正确解释。
