活體超高解析度光譜光學同調斷層掃描系統的研發與皮膚應用

Abstract

非黑色素瘤(non-melanoma skin cancer, NMSC)與黑色素癌(melanoma)的早期偵測對於癒後仍然是一個關鍵的因素，雖然組織切片與組織學檢查是診斷的黃金準則，但進行所有皮膚病灶的組織切片是不可行的，另外目前癌變的發展基本上僅觀察皮膚病灶顏色、形狀和外觀的變化。然而，皮膚表面下的變化基本上是與表面一樣重要。光學同調斷層掃描(Optical Coherence Tomography, OCT)是一種新穎且具有潛力的活體皮膚腫瘤成像技術。在本研究中，我們成功開發一種超高速(45kHz A-scan rate)、超高解析度的光譜域光學同調斷層掃描影像系統，使用超連續光源以達到在組織內小於3μm的軸向解析度，並且可以提供活體人體皮膚組織的三維(three-dimensional, 3D)斷層影像，如血管瘤、痣和甲壁。我們還提出一個”moment”的光譜分析演算法，它可以提供量化的光譜偏態，我們測試幾種類型的仿體包括蓋玻片、奈米合金、含氧血紅素、去氧血紅素。最後，我們運用相同的方法於活體高散射的組織進行測試。

Early detection remains a key factor for non-melanoma skin cancer (NMSC) as well as melanoma for a positive prognosis. Although biopsy and histological examination remain the gold standard for diagnosis, performing biopsies to all skin lesions is not feasible. Besides, currently the cancerous development is basically monitored on the changes in color, shape, texture and appearance of skin lesions. However, the sub-surface changes are fundamentally as important as the surface. Optical Coherence Tomography (OCT) is a new imaging modality with promising potential for in vivo imaging of skin tumor. In this study，we successfully developed an ultrafast(45kHz A-scan rate), ultrahigh resolution spectroscopic spectral domain OCT imaging system, using supercontinuum light source, which can achieve smaller than 3 m axial resolution in tissue and can provide three-dimensional (3D) in vivo tomograms on human skin tissues like Angioma, nevus and the nailfold. We also proposed a spectrum analysis algorithm by using the index of “moment”, which can provide the quantification of spectrum skewness. We tested several kinds of phantom including the cover glass, AuAg alloy nanoparticles, oxygenated hemoglobin and dexoy-hemoglobin. Finally, we implemented the same algorithm on the in vivo highly scattering tissues.