【摘要】：擴(kuò)散光層析成像（Diffuse Optical Tomography，DOT）和熒光層析成像（Fluorescence Diffuse Optical Tomography，，F(xiàn)DOT）技術(shù)由于具有良好的特異性、實(shí)時(shí)性和安全性成為了成像研究的熱點(diǎn)。非接觸式測(cè)量可以獲得大量的測(cè)量數(shù)據(jù)，并且避免了接觸產(chǎn)生的耦合誤差，具有廣闊的應(yīng)用前景。 本文設(shè)計(jì)并搭建穩(wěn)態(tài)域非接觸式DOT/FDOT系統(tǒng)，采用EMCCD（Electron-Multiplying CCD）作為探測(cè)器并輔以待測(cè)體旋轉(zhuǎn)平臺(tái)，以增加源-探測(cè)點(diǎn)數(shù)量，快速獲得大數(shù)據(jù)集，提高系統(tǒng)的空間分辨率。最終形成的系統(tǒng)包括激光器、EMCCD、電控平移臺(tái)/精密電控旋轉(zhuǎn)臺(tái)、濾光輪和計(jì)算機(jī)。 為了充分發(fā)揮該系統(tǒng)獲取大數(shù)據(jù)集的優(yōu)勢(shì)，將系統(tǒng)中的各個(gè)部分進(jìn)行集成，實(shí)現(xiàn)快速測(cè)量、數(shù)據(jù)采集與分析、成像結(jié)果實(shí)時(shí)顯示的自動(dòng)化控制。采用VisualStudio6.0編寫(xiě)系統(tǒng)的控制程序，實(shí)現(xiàn)在連續(xù)測(cè)量模式下，DOT/FDOT系統(tǒng)的自動(dòng)化集成�；诖擞盅芯苛讼到y(tǒng)的校準(zhǔn)方法，以減小像差和噪聲對(duì)成像的影響。并研制了適用于上述非接觸測(cè)量DOT/FDOT用仿體，對(duì)搭建的系統(tǒng)進(jìn)行了DOT及FDOT仿體實(shí)驗(yàn)驗(yàn)證。在DOT測(cè)量中，分別采用不同的源掃描密度、不同吸收系數(shù)的異質(zhì)體及不同中心距（the center-center separation，CCS）的目標(biāo)體進(jìn)行了實(shí)驗(yàn)，并結(jié)合本組已經(jīng)發(fā)展的適合大測(cè)量數(shù)據(jù)集的DOT/FDOT重建算法進(jìn)行了圖像重建。 結(jié)果表明：在最佳光源密度為16×16時(shí)，由該系統(tǒng)所獲得的吸收系數(shù)的重建圖像，能基本反映出異質(zhì)體的形狀、大小和位置；系統(tǒng)可以區(qū)分異質(zhì)體在吸收系數(shù)上的差異，在異質(zhì)體吸收對(duì)比度為2的情況下，重建圖像的量化度高達(dá)70%；系統(tǒng)完全可以分辨最小距離為CCS=12mm的兩個(gè)異質(zhì)體。在FDOT測(cè)量中，分別采用不同的源掃描密度和不同熒光濃度的異質(zhì)體進(jìn)行了實(shí)驗(yàn)。結(jié)果表明：在最佳光源密度即每周30個(gè)點(diǎn)時(shí)，該系統(tǒng)所獲得的熒光產(chǎn)率的重建圖像可以基本反映異質(zhì)體的形狀、大小和位置；且系統(tǒng)可以檢測(cè)出不同熒光濃度下的熒光產(chǎn)率變化。該DOT/FDOT系統(tǒng)有望在小動(dòng)物成像方面發(fā)揮作用。
[Abstract]:Diffusion optical tomography (Diffuse Optical) and fluorescence tomography (Fluorescence Diffuse Optical) have become the focus of imaging research due to their good specificity. Non-contact measurement can obtain a lot of measurement data and avoid the coupling error caused by contact, so it has a broad application prospect. In this paper, a steady state non-contact DOT/FDOT system is designed and built. EMCCD (Electron-Multiplying CCD) is used as the detector and a rotating platform is used to increase the number of source-probe points, to obtain big data sets quickly and to improve the spatial resolution of the system. The resulting system consists of a laser EMCCD, an electrically controlled translation platform / a precision electrically controlled rotation table, a filter wheel and a computer. In order to give full play to the advantages of the system in obtaining big data sets, the system integrates all parts of the system to realize the automatic control of rapid measurement, data acquisition and analysis, and real-time display of imaging results. The automatic integration of DOT / FDOT system in continuous measurement mode is realized by programming the control program of the system with VisualStudio6.0. Based on this, the calibration method of the system is studied to reduce the influence of aberration and noise on the imaging. The simulant used in the above non-contact measurement of DOT/FDOT was developed. The system was verified by DOT and FDOT experiments. In the DOT measurement, different source scanning density, different absorption coefficient and different the center-center separation distance were used to carry out the experiments. Combined with the developed DOT/FDOT reconstruction algorithm for large measurement data sets, image reconstruction is carried out. The results show that when the optimum light density is 16 脳 16:00, the reconstructed image of the absorption coefficient obtained by the system can basically reflect the shape, size and location of the heterogeneity, and the system can distinguish the difference of the absorption coefficient of the heterogeneity. The quantization of the reconstructed image is as high as 70 when the absorption contrast of the heterostructure is 2, and the system can fully distinguish the two heterostructures with the minimum distance of CCS=12mm. In the FDOT measurement, different source scanning densities and different fluorescence concentrations were used to carry out the experiment. The results show that the reconstructed image of fluorescence yield obtained by the system can basically reflect the shape, size and location of the heterostructure when the optimal light density is 30 points per week. The system can detect the change of fluorescence yield under different fluorescence concentration. The DOT/FDOT system is expected to play a role in the imaging of small animals.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類(lèi)號(hào)】：R310

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