Graduate School of Medical Photonics, Shizuoka University, Hamamatsu 432-8561, Japan.
Division of Vascular Surgery, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
Sensors (Basel). 2021 Aug 19;21(16):5573. doi: 10.3390/s21165573.
Tissue oxygenation sensing at a few millimeters deep is useful for surgical and postoperative management. However, the measurement sensitivity at each depth and the proper sensor combination have not been clarified. Here, the measurement characteristics of oximetry by spatially resolved near-infrared spectroscopy were analyzed using Monte Carlo simulation and phantom experiment. From summing the sensitivities of each depth, it was quantitatively found that the measurement sensitivity curve had a peak, and the measurement depth can be adjusted by combining the two distances between the light source and the detector. Furthermore, the gastric tissue was 10-20% smaller in terms of measurement depth than the skin-subcutaneous tissue. A miniaturized oximeter was prototyped so that it could be used in combination with an endoscope or laparoscope. The optical probes consisted of light emitting diodes with wavelengths of 770 nm and 830 nm and photodetectors located 3 to 30 mm from the light source. Phantom experiments using the probes demonstrated the tendency of theoretical analysis. These results suggest the possibility of measuring tissue oxygen saturation with a selectable measurement depth. This selectable method will be useful for obtaining oxygenation information at a depth of 2-5 mm, which is difficult to measure using only laparoscopic surface imaging.
组织氧合在几毫米深的部位进行探测对于手术和术后管理很有用。然而，各深度的测量灵敏度以及合适的传感器组合尚未得到明确。在这里，我们使用蒙特卡罗模拟和体模实验分析了空间分辨近红外光谱血氧测定的测量特性。通过对各深度的灵敏度进行求和，我们定量地发现，测量灵敏度曲线具有峰值，并且可以通过组合光源和探测器之间的两个距离来调整测量深度。此外，与皮肤-皮下组织相比，胃组织的测量深度小 10-20%。我们还制作了一种小型化的血氧计，可以与内窥镜或腹腔镜结合使用。光学探头由波长为 770nm 和 830nm 的发光二极管和位于光源 3 至 30mm 处的光电探测器组成。使用探头进行的体模实验证实了理论分析的趋势。这些结果表明，通过选择测量深度来测量组织氧饱和度是可能的。这种可选方法将有助于获取仅使用腹腔镜表面成像难以测量的 2-5mm 深度处的氧合信息。
