移動式漫反射光譜系統建立與人體口腔黏膜參數萃取

Abstract

本研究主旨為建構一結合高光譜儀與影像光纖束之移動式漫反射光譜系統，於臨床情況下量取口腔黏膜的空間漫反射光譜資訊，再透過漫反射光譜擬合工具進行組織光學參數之萃取，以期可提供早期癌症診斷之輔助判斷資訊。 本系統安裝了用於漫反射訊號量測之寬頻可見光源，並於量測上使用兩種不同形式之光纖束，分別為斜角及平口光纖束，可應用於淺層及較深層組織之訊號量測，斜角光纖束使用為沿影像光纖束中心軸由光源光纖向外圈選圓形區域(Region of interest, ROI)之分析模式，平口光纖束則以光源光纖為中心，向外圈選同心圓環進行分析。 本系統以驗證後之蒙地卡羅順向模擬光譜進行組織漫反射光譜校正，於影像光纖束上選取至光源不同距離 (source to detection separation, SDS) 之偵測範圍分析，並以四種不同濃度尺寸之液態散射源(polystyrene)及擬組織雙層仿體(phantom)進行空間漫反射光譜的量測校正比對，於SDS = 300、400、600、800 μ'm' 之偵測範圍，液態散射源的方均根誤差值可達到6%以內、擬組織雙層仿體亦有8%以內的水準，由此可知本系統之漫反射光譜量測已達到相當程度的準確率。 本系統已通過衛生署及本校醫學院附設醫院醫工部核可，於本校醫學院附設醫院針對正常與病變人體口腔黏膜組織進行臨床量測，除使用反向模型擬合工具萃取出口腔黏膜於450 nm至700 nm波段之光學參數定量分析外，亦直接統計光譜形狀特徵做定性分析。預計本系統未來可建立光學參數與光譜特徵資料庫，作為判斷癌前病變進程的依據之一。 本移動式系統之目標為一穩定可靠的臨床量測系統，並能提供癌前病變診斷的輔助資訊。

The main idea of this research is to construct a portable diffuse reflectance spectral system by combining a hyper-spectral imaging system and a fiber bundle. In order to provide information on early cancer diagnosis, we gather the spatially-resolved diffuse reflectance spectrum of oral mucosa in clinical settings and use the fitting tool to quantify the optical parameters of it. For diffuse reflectance spectrum measurement, we use the broad band visible light source and two kinds of imaging fiber bundle in our system. One is the perpendicular distal end and one is the 45 degree oblique distal end of the imaging fiber bundle respectively for the shallow and deep tissue. According to the different sources of detection separation (SDS), we select the concentric ring region of interest (ROI) on perpendicular imaging fiber bundle and circle region of interest on oblique imaging fiber bundle along the long and short axes, respectively. The system, calibrated by the verified Monte Carlo simulation spectrum, measures the polystyrene liquid scattering phantom in four different diameters and concentrations and measures the tissue-mimic two layered phantom. In the SDS of 300, 400, 600, and 800 micrometers, the root mean square error is less than 6% in liquid scattering phantom and 8% in two layered phantom, showing our system has good accuracy. Approved by Taiwan Food and Drug Administration (TFDA), Department of Health and National Taiwan University Hospital Medical Industry, we have clinical measurement in Department of Dentistry National Taiwan University Hospital for oral mucosa. In addition to using a fitting tool quantifying the optical parameters in 450-700 nanometers, we also collect statistics directly for spectrum principle component analysis (PCA). The system is expected to build future optical parameters and spectral characteristics of the database as a judgment basis for the process of the precancerous lesions. The portable system’s objective is to be a stable and reliable clinical measurement system and to provide supplementary information of the precancerous lesions.