摘要 擴散式光學斷層掃描是一種新型的斷層造影技術，其優點是對於人體不具有侵入性和幅射傷害。本論文描述一個自行搭建的近紅外光斷層掃瞄設備，並且使用人造假體去模擬生理組織。所使用的近紅外光斷層掃瞄術設備，搭建在一個旋轉機構上，以單一光源和偵測器藉由旋轉機構掃瞄人造假體，從而獲得實驗數據。人造假體則是使用高散射微形球和人造脂類Intralipid去模擬生理組織的吸收與散射等光學特性；藉由人造假體的幫助，可以免除量測真正的生理組織光學特性，而能得到相似的實驗結果。在光學特性影像重建的反算法部份，初始猜值相當重要，同樣的組織周圍光功率量測結果，可能因為初始猜值的差異，而造成重建影像與實際狀況截然不同，這也就是影像反算並非唯一解。本研究進行並建立人造假體技術，將能完成實驗結果的資料庫，幫助影像重建初始猜值的正確性，並能加快影像重建的速度。論文研究中，提出一個擬態模型的方法，這個擬態模型是使用1% Intralipid去模擬豬肉，3% Intralipid去模擬骨頭；使用擬態模型的目的，是為了要得到和真實組織量測訊號相似的分佈，由於擬態模型的訊號強度往往比真實組織要大，較好量測，現階段可以較不受硬體之限制，對於發展擴散式光學斷層掃瞄技術極有助益。 Abstract Diffuse optical tomography is a new tomographic technique. Its advantages include noninvasive and nonradiation to human body. The thesis describes an self-developed NIR diffuse optical tomography instrument based on rotary mechanism, and conducts a phantom study for simulating biological tissues. The NIR tomography system is built on a rotary scanning device associated with single rotating source and detector to scan designed phantoms and acquire experimental data. The phantoms are constructed by employing high-scattering polystyrene microspheres and Intralipid to mimic the scattering and absorption properties of tissues. With the help of phantoms, similar experimental results can be obtained without measuring real tissues. In the computation of optical-property image reconstruction, appropriate initial guess is crucial. The reconstructed image from measured optical power around tissues may be totally different from actual state just due to different initial guess. It says the result of image reconstruction using inverse computation is in general not a unique solution. The study performs a phantom technique and completes a experimental data base. This helps the accuracy of the initial guess and speeds up the image reconstruction afterwards. Additional, a pseudo-model technique for real tissues is proposed and performed. The pseudo-model is to employ 1 % Intralipid as a background tissue and 3 % Intralipid as an inclusion to mimic a bone. The purpose of using pseudo-model is to obtain the similar distribution of signal from real tissues. The intensity of pseudo-model signal is greater than that of real tissues signal so the signal can be acquired. The measurement would not be limited by hardware constraint. The technique offers a great aid for the development of diffuse optical tomography.
