使用超連續雷射光源的高解析度高靈敏度光譜域光學同調斷層掃描術
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2012
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本篇論文的主題在於以超連續白光雷射作為光源，建構一套具有高解析度與高靈敏度的光譜域光學同調斷層顯微術(Spectral Domain Optical Coherence Tomography, SD-OCT)。於系統架構中我們引入了平衡式偵測法(Balance Detection, BD)，不僅能夠提升干涉訊號為兩倍，還能夠大幅度的降低自相干雜訊與直流項。經由實驗證明這套以平衡式偵測法為架構的高解析度高靈敏度SD-OCT系統能夠提供於生物樣品中達2m的縱向解析力，最快的成像速度可以達到每秒45,000條軸向掃描，其中每條為4096個畫素。在訊雜比部分，我們證明了於1mm的成像深度內能夠較一般的SD-OCT系統提升8~14dB的訊雜比。我們也將系統用於蓋玻片、膠帶來測試效能，並且實際應用於人類的甲襞微血管與手掌汗腺這兩種生物樣品的活體掃描。最後，我們嘗試使用貝索光束(Bessel beam)來延長這套高解析高靈敏的SD-OCT系統的景深。
In this study, we present a new high resolution and high sensitivity spectral domain optical coherence tomography (SD-OCT) system that profits from the enhanced resolution performance of supercontinuum laser. The use and advantages of balanced detection (BD) in this system are also demonstrated. Not only does this system suppress artifacts due to autocorrelation, but also the signal of interest is increased by a factor of 2 as experimentally verified. Our BD-based high resolution SD-OCT gives an axial resolution of near 2 m in tissue and 45,000 axial scans per second at 4096 pixels per axial scan. A signal-to-noise ratio (SNR) improvement of a 8~14 dB for the peak within 1 mm compared to standard SD-OCT using single detection scheme was also demonstrated. This method is validated by experimental measurement of a glass plate, adhesive tape, and in vivo imaging of the human capillary under nailfold and sweat gland on palm. Finally, we also verified the possibility of using Bessel beam illumination to extend the depth of focus in our proposed high resolution and high sensitivity SD-OCT system.
In this study, we present a new high resolution and high sensitivity spectral domain optical coherence tomography (SD-OCT) system that profits from the enhanced resolution performance of supercontinuum laser. The use and advantages of balanced detection (BD) in this system are also demonstrated. Not only does this system suppress artifacts due to autocorrelation, but also the signal of interest is increased by a factor of 2 as experimentally verified. Our BD-based high resolution SD-OCT gives an axial resolution of near 2 m in tissue and 45,000 axial scans per second at 4096 pixels per axial scan. A signal-to-noise ratio (SNR) improvement of a 8~14 dB for the peak within 1 mm compared to standard SD-OCT using single detection scheme was also demonstrated. This method is validated by experimental measurement of a glass plate, adhesive tape, and in vivo imaging of the human capillary under nailfold and sweat gland on palm. Finally, we also verified the possibility of using Bessel beam illumination to extend the depth of focus in our proposed high resolution and high sensitivity SD-OCT system.
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OCT, OCT