偏振敏感光學同調斷層掃描即時影像在牙科之應用

Abstract

光學同調斷層掃描術(Optical coherence tomography, 簡稱OCT )是一種非侵入式且廣泛運用在眼科醫學上的儀器，其原理是運用超快速掃頻雷射(swept-source laser)，搭配上光學干涉儀與光偵測器後得到強度與深度的資訊，除了一般原始架構的光學同調斷層掃描術之外，本研究還運用光的偏振特性，使其與OCT系統做結合，稱偏振敏感光學同調斷層掃描術(Polarization-sensitive Optical coherence tomography, 簡稱PS-OCT)。在此論文中我們使用偏振敏感光學同調斷層掃描術來量化牙齒疾病(牙結石)，偏振敏感光學同調斷層掃描術是針對不同組織對偏振光產生的不相同結果，像是雙折射晶體產生的相位延遲影像在表面會有規律的相位差異。實驗結果發現正常牙齒與牙結石在相位延遲影像下會有不同的特徵，可以明顯的辨別出牙結石與正常牙齒，讓醫師可以對確切的病徵提出正確的治療方式，因此利用偏振敏感光學同調斷層掃描術來量化口腔硬組織是可行的。未來我們會再利用光學探頭以利臨床口腔診斷量測，提供醫生明確的資訊以利診斷。

Optical coherence tomography is a novel technology for medical imaging. The advantage of optical coherence tomography is non-contact, non-invasive and high-resolution (10-6m). Swept-source OCT use fast scanning laser as light source and photo balance detector to sample the data. In our research we combine the polarization property with the system called polarization sensitive optical coherence tomography (PS-OCT). Polarization-sensitive optical tomography is functional extension of standard OCT. It can observe the different of birefringence material. We apply the PS-OCT to dental diagnosis. Normal tooth and calculus have different structure. Enamel is birefringence material, it has the regular phase change. Structure of calculus is different with enamel, due to the mineral accumulation the structure of calculus show the random polarization on phase retardation. According to this we use distinguish the normal tooth and calculus by phase retardation image. In the future, we will combine hand-hold probe, hope can apply on clinical diagnosis and help doctor have better information for right treatment.