【摘要】：光學(xué)相干層析成像(Optical Coherence Tomography, OCT)是一門新型的成像技術(shù),具有無輻射、非接觸、高探測靈敏度及高分辨率等特點,引起了眾多生物醫(yī)學(xué)領(lǐng)域科研工作者的關(guān)注。光譜OCT是第二代OCT技術(shù),相比第一代時域OCT技術(shù),它在成像速度、信噪比和靈敏度等方面都具有明顯優(yōu)勢,在眼科成像、小動物成像等領(lǐng)域發(fā)揮了重要作用,具有廣闊的臨床和研究前景。首先,介紹光譜OCT成像技術(shù)理論。從光和生物組織的相互作用出發(fā),定性解釋了光的散射過程。對光譜OCT系統(tǒng)結(jié)構(gòu)進行分析,指出其優(yōu)越性。闡釋OCT成像技術(shù)的基本理論,包括低相干干涉理論和共焦顯微術(shù)理論。在分析光譜OCT信號成分的基礎(chǔ)上,指出有效信號項和噪聲項。討論光譜OCT成像系統(tǒng)的主要參數(shù)。 其次,搭建快速高分辨光譜OCT成像系統(tǒng),并進行詳細(xì)說明�；�2×2光纖耦合器(50/50)對整個系統(tǒng)的干涉光路進行設(shè)計。采用2D光學(xué)掃描振鏡搭建光路掃描系統(tǒng),此光學(xué)掃描振鏡由數(shù)據(jù)采集卡控制。采用超快線陣CCD相機和1145線/mmm光柵對光譜采集系統(tǒng)進行搭建,并通過圖像采集卡把采集到的光譜傳輸給計算機。采用光譜坐標(biāo)校正法對系統(tǒng)進行色散補償。指出圖像計算的方法,并討論光源的選擇問題。 最后,應(yīng)用所搭建的光譜OCT成像系統(tǒng)進行相位相關(guān)流速測量實驗。光譜OCT成像技術(shù)與多普勒效應(yīng)相結(jié)合,通過相位差可以求出流動粒子的速度信息。通過理論分析選取勻速橫向掃描方式,并對系統(tǒng)的相位穩(wěn)定性進行評估。分析系統(tǒng)模式噪聲和相位噪聲的產(chǎn)生機理,并分別采用B掃描平均法和往返程掃描法,成功的消除了系統(tǒng)噪聲。針對相位卷繞現(xiàn)象采用相位常數(shù)法,消除了此現(xiàn)象,并使流速測量范圍擴大了一倍。應(yīng)用本系統(tǒng)對早期雞胚胎心臟的血流速度進行活體測量,定量分析了血流分布情況。 綜上所述,我們搭建了一套快速高分辨率的光譜OCT成像系統(tǒng),并應(yīng)用該系統(tǒng)進行了相位相關(guān)流速測量實驗。通過本課題的研究實現(xiàn)了成像時間短、分辨率高及測量范圍大的光譜OCT成像系統(tǒng),對臨床醫(yī)學(xué)應(yīng)用起到了推進作用。
文內(nèi)圖片：
圖片說明：光譜OCT原理圖（BS:BeamSplitter)
[Abstract]:Optical coherence tomography (Optical Coherence Tomography, OCT) is a new imaging technology, which has the characteristics of no radiation, non-contact, high detection sensitivity and high resolution, which has attracted the attention of many researchers in biomedical field. Spectral OCT is the second generation OCT technology. Compared with the first generation time domain OCT technology, it has obvious advantages in imaging speed, signal-to-noise ratio (SNR) and sensitivity. It plays an important role in ophthalmic imaging, small animal imaging and other fields, and has broad clinical and research prospects. Firstly, the theory of spectral OCT imaging technology is introduced. Based on the interaction between light and biological tissue, the scattering process of light is explained qualitatively. The structure of spectral OCT system is analyzed and its advantages are pointed out. The basic theories of OCT imaging technology, including low coherence interference theory and confocal microscopy theory, are explained. On the basis of analyzing the signal components of spectral OCT, the effective signal terms and noise terms are pointed out. The main parameters of spectral OCT imaging system are discussed. Secondly, a fast high resolution spectral OCT imaging system is built and described in detail. The interference optical path of the whole system is designed based on 2 脳 2 fiber couplers (50 脳 50). The optical path scanning system is constructed by using 2D optical scanning mirror, which is controlled by data acquisition card. The spectral acquisition system is built by using ultra-fast linear CCD camera and 1145 line / mmm grating, and the collected spectrum is transmitted to the computer through the image acquisition card. The spectral coordinate correction method is used to compensate the dispersion of the system. The method of image calculation is pointed out, and the selection of light source is discussed. Finally, the phase correlation velocity measurement experiment is carried out by using the spectral OCT imaging system. Combining spectral OCT imaging with Doppler effect, the velocity information of flow particles can be obtained by phase difference. Through theoretical analysis, the uniform transverse scanning mode is selected, and the phase stability of the system is evaluated. The generation mechanism of mode noise and phase noise of the system is analyzed, and the B scan average method and the round trip scanning method are used to eliminate the system noise successfully. The phase constant method is used to eliminate this phenomenon and double the range of velocity measurement. The blood flow velocity of early chicken embryo heart was measured in vivo by this system, and the blood flow distribution was analyzed quantitatively. To sum up, we built a set of fast and high-resolution spectral OCT imaging system, and used the system to measure the phase-dependent velocity. Through the research of this subject, a spectral OCT imaging system with short imaging time, high resolution and wide measurement range is realized, which plays an important role in clinical medical application.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R310;O433

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本文編號：2511987