In order to achieve high-sensitivity time-domain diffuse correlation spectroscopy (TD-DCS) measurement of functional changes in cerebral blood flow, this study applied simulation methods to optimize the TD-DCS system under real experimental conditions (including the consideration of the effects of finite coherence length LC and non-ideal instrument response function IRF). Under a real experimental condition where the incident power is 75 mW, the source-detector distance is 1.0 cm, and the full width at half maxima of the IRF is 160 ps, we used simulation experiments to investigate the relationship between the contrast of the intensity autocorrelation function (g2) in two brain functional states (i.e., baseline and activation) and TD-DCS system parameters (including LC, IRF, source-detector distance, gate opening time and gate width).Our simulation results show that both longer LC and longer integration time are beneficial to a more sensitive detection. With a fixed LC and integration time, the optimal parameters of gate opening time is 800 ps (relative to the peak time of IRF), and gate width is equal to or larger than 800 ps. This study may be useful for guiding the sensitive measurement of human brain functions (e.g., changes in cerebral blood flow) using the TD-DCS technology.

中文翻译：

---

检测人脑功能的时域漫相关光谱：通过仿真方法在真实实验条件下优化系统


为了实现脑血流功能变化的高灵敏度时域漫相关光谱（TD-DCS）测量，本研究应用仿真方法在真实实验条件下（包括考虑影响因素）对TD-DCS系统进行优化有限相干长度 LC 和非理想仪器响应函数 IRF）。在入射功率为75 mW、光源-探测器距离为1.0 cm、IRF半峰全宽为160 ps的真实实验条件下，我们通过仿真实验研究了强度对比度之间的关系。两种大脑功能状态（即基线和激活）下的自相关函数（g2）和TD-DCS系统参数（包括LC、IRF、源-探测器距离、门打开时间和门宽度）。我们的模拟结果表明，较长的LC较长的积分时间有利于更灵敏的检测。在LC和积分时间固定的情况下，栅极开启时间的最佳参数为800 ps（相对于IRF的峰值时间），栅极宽度等于或大于800 ps。这项研究可能有助于指导使用TD-DCS技术对人脑功能（例如脑血流量的变化）进行灵敏测量。