利用傅立葉轉換式高光譜顯微影像系統進行口腔黏膜光學參數量測

Abstract

本研究利用傅立葉轉換式高光譜影像顯微系統結合影像光纖，同時量測取得不同距離之漫反射光譜資訊，並且利用光譜擬合工具進行口腔黏膜組織光學參數的萃取以及血氧濃度和血紅素濃度的定量研究。 本研究利用縮放式蒙地卡羅法做為順向模型，利用雙層組織模型建立口腔空間漫反射光譜，並利用Levenberg-Marquart演算法建立反向模型進行光譜擬合，希望同時萃取出口腔雙層組織光學參數以及厚度之資訊。並利用帶有雜訊之口腔模擬漫反射光譜進行擬合工具的驗證，結果顯示結合多光纖的漫反射資訊進行光譜擬合，可同時萃取出雙層之吸收係數及散射係數，並可同時得知上層組織厚度，且其方均根誤差皆在10%以下。 本研究利用仿體進行系統之驗證，利用polystyrene小球為散射子並以紅墨水為吸收子進行單層組織的光學模型模擬，並利用校正仿體消除系統響應，成功得到距離為0.4mm ~1.8 mm之光纖空間漫反射資訊。光譜擬合結果顯示本研究方法對於均值單層仿體的光學參數萃取準確率其小球濃度、小球直徑以及紅墨水濃度的平均百分誤差率分別為0.72%、-1.6%、3.5%，吸收係數與減少散射係數的方均根誤差分別為4.33%及2.5%。雙層組織模擬的量測驗證上，利用二氧化鈦當做散射子及紅墨水為吸收子並分別以PDMS及洋菜膠為基質進行量測找出最佳的製作與量測方法，實驗光譜擬合萃取出之輸入光學參數的誤差百分率皆在15%以下。 本研究實際量測口腔側面黏膜之漫反射光譜，並利用一標準仿體進行系統響應的修正，成功量測出口腔黏膜於450 nm至800 nm之空間漫反射光譜資訊，並將其以光學萃取工具進行光譜擬合成功萃取出雙層口腔黏膜組織的光學參數。

In this thesis, we used a Fourier transfer hyperspectral image-based microscopy spectrometer combined with a imaging fiber-optic bundle to measure reflectance spectrum at different source-detector separation. We also used a fitting tool to extract the optical parameters and quantify the hemoglobin concentration and oxygen saturation. We used scaling Monte carlo as the forward model to construct a two-layer oral mucosa spatially-resolved reflectance spectrum. In inversed model, we used Levenberg-Marquart algorism to fitting reflectance spectrum, in order to extract the optical parameters and the thickness of epithelium. We used a oral simulated oral spatially-resolved reflectance spectrum with random noise to validate fitting tool. The result indicate that combined with multi-fiber reflectance spectrum, we can extract the absorption and reduced scattering coefficients of oral double-layer tissue simultaneously and get the thickness of the epithelium. The root mean square error of optical parameters are all below 10%. We used phantom to validate the study method. We choose polystyrene sphere as scatter, red ink as absorber and water as medium to simulate a single-layer tissue phantom, and used a standard phantom to calibration reflectance spectrum, and get spatially-resolved reflectance spectrum successfully by our optical system. The mean percent error of our measuring method to extract the optical parameters of homogeneous phantom is 0.72%、-1.6%、3.5% for polystyrene concentration, polystyrene diameter and red ink concentration, respectively. The root mean square error of absorption coefficients and reduced scattering coefficients is 4.33% and 2.5%. For two-layer tissue validation, we used TiO2 as scatter and red ink as absorber to fabricate two-layer phantom, and used PDMS and agar as medium to compare the measurement results and to find the best phantom fabrication and measurement protocol. The extracted optical parameters are all below 15%. We used Fourier transfer hyperspectral image-based microscopy spectrometer to measure the reflectance spectrum of oral mucosa, and used a standard phantom to calibration the system response. Successfully get the reflectance of oral mucosa at wavelength range of 450 nm to 800 nm and using the optical parameter extracting tool to get the normal human oral mucosa optical parameters.