采用不同的光传输模型比较研究结肠的散射和吸收特性:离体结肠肿瘤的光学诊断

测定和比较研究了离体的正常的和腺癌的人结肠粘膜/粘膜下层以及正常的和腺癌的人结肠肌层/浆膜组织对630 nm,680 nm,720 nm,780 nm,810 nm,850 nm和890 nm波长的钛宝石激光的散射和吸收系数。采用双积分球测量系统测量组织样品对七个不同波长的激光的准直透射、漫反射和漫透射,从实验所测结果以及分别采用反向倍增法和反演蒙特卡罗技术这两个光学模型计算出组织的散射和吸收系数。研究结果表明,无论是用反向倍增法还是用反演蒙特卡罗法,每一种类型的正常的和腺癌的人结肠组织对同一波长的激光的吸收系数和散射系数有显著性的差异(P<0.01),正常的和腺癌的结肠组织的散射和吸收系数有大的差异,这些结果提示每种类型的正常和腺癌的结肠组织的组份和结构之间有大的差异。四种类型的结肠组织对七个不同波长的激光的散射系数较其吸收系数至少要大三个数量级,而四种类型的结肠组织对七个不同波长的激光的散射系数有相同的数量级。

Comparative Study of the Scattering and Absorption Properties for Colon Tumor Diagnosis: an in vitro Study Using Different Light Propagation Model

The scattering and absorption coefficients were determined and compared in vitro for normal and adenomatoushuman colon mucosa/submucosa,and normal and adenomatous human colon muscle layer/chorion at630 nm,680 nm,720 nm,780 nm,810 nm,850 nm and 890 nm of Ti:S ring laser.Tissue samples were measured with a double in-tegrating sphere set-up to determine their collimated transmission,diffuse reflectance and diffuse transmission at sevenlaser wavelengths.The inverse adding-doubling algorithm and inverse Monte Carlo simulation were respectively used tocalculate the scattering and absorption coefficients from the measurements.The investigative results showed that therewere significant differences in the absorption and scattering coefficients between normal and adenomatous human colontissues per tissue type at the same laser wavelength(P<0.01),whether using the inverse adding doubling method or u-sing the inverse Monte Carlo simulation.These large differences of the absolute values in the scattering and absorptioncoefficients indicate that there were large differences in compositions and structures between normal and adenomatous hu-man colon tissues per tissue type.The scattering coefficients of colon tissues exceed the absorption coefficients by at leastthree orders of magnitude,and there are same orders of magnitude in the scattering coefficients for four kinds of colon tis-sues.