This paper demonstrates a method to estimate the depth of a fluorescence object in turbid media using dual-wavelength excited photodynamic diagnosis, to aid in the invasion depth diagnosis of gastric cancer. The treatment method for gastric cancer is determined by its invasion depth, which is difficult to measure in situ during endoscopic diagnosis. Therefore, a method that can quantitatively diagnose tumor depth using a simple optical system that can be utilized with an endoscope is required. In the proposed method, the depth of a fluorescence object in a turbid medium is estimated by considering the optical propagation of two wavelengths of excitation light and absorption properties of protoporphyrin IX. In our experiments, we evaluated the estimation accuracy of the fluorescence object depth in a tissue-mimicking phantom from a fluorescence intensity ratio during fluorescence observation based on the calibration curve obtained from prior numerical calculation. The results of the fluorescence observation experiment showed that the depth of the fluorescence object could be estimated with an error of less than 0.3 mm within 2 mm from the surface.

本文展示了一种利用双波长激发光动力学诊断来估计混浊介质中荧光物体深度的方法，以帮助诊断胃癌的侵袭深度。胃癌的治疗方法取决于其浸润深度，内镜诊断时难以原位测量。因此，需要一种可以使用可与内窥镜一起使用的简单光学系统来定量诊断肿瘤深度的方法。在所提出的方法中，通过考虑两个波长的激发光的光传播和原卟啉 IX 的吸收特性来估计混浊介质中荧光物体的深度。在我们的实验中，我们根据先前数值计算获得的校准曲线，根据荧光观察期间的荧光强度比评估了组织模拟体模中荧光物体深度的估计精度。荧光观察实验结果表明，荧光物体的深度可以在距地表2毫米以内的误差小于0.3毫米的范围内进行估计。