本文采用Monte Carlo模拟人体肠道组织的非接触式漫反射光谱,并分别研究了聚焦光束的聚焦深度、组织表面入射光斑与出射光斑(Source-Detector,S-D)之间的距离、探测面积和探测深度对光谱测量的影响,为设计非接触式光谱检测系统提供理论依据.结果表明在利用光谱技术对肠道疾病如早期肠癌进行诊断时,非接触式光谱检测系统的聚焦深度应小于0.1 cm;在漫反射光谱检测时,应根据探测信号的强弱以及探测器的灵敏度选择S-D距离;0.06 cm的探测面积半径能有效地反映组织中氧合血红蛋白和脱氧合血红蛋白含量的变化情况;为反映不同深度组织光学特性,在改变探测深度时,应保持探测光锥顶角不变.

Monte Carlo simulation was applied to analyze the light distribution of the converging light beam in the homogenous intestinal tissue model.The influence of the depth of focus,detection area and source-detector distance on the diffuse reflectance spectroscopy measurement were quantitatively investigated.The results show that the optimal focus depth of the non-contact spectrum system for the diagnosis of the intestinal lesions in situ is 0.1 cm.For the diffuse reflectance spectroscopy measurement,the source-detector distance can be determined by the intensity of emission light and the response sensitivity of detector.0.06 cm is the optimal detection radius for correctly reflecting the change of the content of oxyhemoglobin and deoxygenated hemoglobin using diffuse reflectance spectroscopy.In order to reduce the influence on the spectrum caused by the change of detection depth,the apex angle of detection light cone should be constant.