發(fā)布時(shí)間：2018-04-24 06:55

  本文選題：醫(yī)學(xué)成像 + 光學(xué)相干層析術(shù)　； 參考：《南京理工大學(xué)》2016年博士論文

【摘要】：光學(xué)相干層析術(shù)(Optical Coherence Tomography,OCT)是20世紀(jì)90年代提出的一種可對生物組織活體斷層成像的方法,具有分辨率高、成像速度快和對樣品無損傷等優(yōu)點(diǎn)。該技術(shù)利用生物組織的后向散射光與參考光的干涉信號來提取生物組織深度方向上的信息,在橫向上則利用兩個(gè)掃描振鏡進(jìn)行二維掃描,經(jīng)過數(shù)據(jù)處理來重構(gòu)樣品的三維圖像。該成像技術(shù)的分辨率為微米量級,在組織中的最大成像深度能夠達(dá)到2 mm。人體所需的營養(yǎng)物質(zhì)和氧氣都是通過血液循環(huán)輸送到全身各組織,并且在毛細(xì)血管中發(fā)生物質(zhì)交換。當(dāng)組織發(fā)生病變時(shí),血管的分布也會發(fā)生相應(yīng)的變化。因此在臨床醫(yī)學(xué)中,組織中的血管分布圖像可以輔助疾病診斷,如癌癥,牛皮癬和酒色斑等疾病。本文首先設(shè)計(jì)并搭建了一臺譜域OCT系統(tǒng)(Spectral Domain OCT,SDOCT),然后主要對基于OCT的血流成像技術(shù)進(jìn)行了研究。主要內(nèi)容包括下面幾個(gè)方面:首先設(shè)計(jì)并搭建了一臺SDOCT系統(tǒng)。為了優(yōu)化系統(tǒng)性能,搭建了一套快速掃描延遲線系統(tǒng)來補(bǔ)償該系統(tǒng)色散。為了提高色散補(bǔ)償精度,提出通過測量參考臂和樣品臂色散不匹配值的方法來評定色散補(bǔ)償效果;同時(shí)提出基于該系統(tǒng)的測量透射樣品色散值和折射率的方法。為了抑制活體成像過程中環(huán)境抖動和系統(tǒng)不穩(wěn)定等在相位差圖像中引入的隨機(jī)噪聲,提出基于譜域互相關(guān)的相位分辨多普勒OCT技術(shù)來計(jì)算組織中的血流速度。該方法中,對連續(xù)兩次A掃的干涉條紋信號通過互相關(guān)運(yùn)算來去除噪聲。在血流模擬實(shí)驗(yàn)中,新方法將速度信號的信噪比由53 dB提高到56 dB;在對老鼠耳朵上血流成像的實(shí)驗(yàn)中,該方法將速度信號的信噪比由45 dB提高到49 dB。為了解決相關(guān)成像OCT方法中血流圖像分辨率和血流圖像信噪比之間的矛盾,提出…基于體數(shù)據(jù)的相關(guān)成像OCT方法來重構(gòu)血流圖像,實(shí)現(xiàn)在不減小XZ 載面內(nèi)圖像分辨率的情況下提高血流圖像的質(zhì)量。實(shí)驗(yàn)結(jié)果證明窗口為3×3×3像素時(shí)基于體數(shù)據(jù)的相關(guān)成像OCT方法所得血流信號的信噪比比窗口為7×7像素時(shí)傳統(tǒng)相關(guān)成像OCT方法所得血流信號的信噪比高2 dB,并且血流圖像的分辨率高了近一倍。為了去除相關(guān)成像OCT方法中由呼吸和心跳等引起的抖動噪聲,提出利用補(bǔ)零技術(shù)和圖像配準(zhǔn)技術(shù)來對結(jié)構(gòu)圖像進(jìn)行配準(zhǔn),再通過計(jì)算相關(guān)系數(shù)的方法提取血流信號。為了提高提取血流信號的靈敏度,提出利用OCT圖像中的虛部信號來計(jì)算相關(guān)系數(shù)。實(shí)驗(yàn)結(jié)果證明在人體皮膚的血流圖像中,補(bǔ)零技術(shù)和圖像配準(zhǔn)技術(shù)能夠有效地去除抖動噪聲;在老鼠耳朵血流成像實(shí)驗(yàn)中,基于虛部相關(guān)的方法能夠提取出更多的血流信號,包括傳統(tǒng)相關(guān)成像OCT方法未能提取的小血管信號。為了提高血流圖像質(zhì)量,提出利用多光束掃描方法來抑制血流圖像中的噪聲,分析了樣品位于測量光束焦點(diǎn)之外時(shí)對多普勒相位和散斑方差的影響并通過血流模擬實(shí)驗(yàn)來驗(yàn)證了理論;最后,通過人體皮膚成像實(shí)驗(yàn)來證明了多光束掃描方法能夠應(yīng)用在相位分辨多普勒OCT,相位分辨多普勒方差OCT和散斑方差OCT方法中來提高所得血流圖像的質(zhì)量。
[Abstract]:Optical Coherence Tomography (OCT) is a method of imaging of living tissue in biological tissue in 1990s. It has the advantages of high resolution, fast imaging speed and no damage to the sample. This technique uses the backscatter light of biological tissue and the interference signal of reference light to extract biological tissue depth. In the direction of information, two scanning mirrors are scanned horizontally, and the three-dimensional image of the sample is reconstructed through data processing. The resolution of the imaging technique is micron. The nutrients and oxygen required for the maximum imaging depth of the tissue to reach 2 mm. human body are circularly transported through the blood to the whole body. Tissue, and material exchange in capillaries. When tissue changes, the distribution of blood vessels also changes. Therefore, in clinical medicine, the distribution of blood vessels in the tissue can assist the diagnosis of disease, such as cancer, psoriasis and wine stains. In this paper, a spectral domain OCT system (Spectral) is designed and built in this paper. Domain OCT, SDOCT), and then mainly study the blood flow imaging technology based on OCT. The main contents include the following aspects: first design and build a SDOCT system. In order to optimize the system performance, a set of fast scanning delay line system is set up to compensate the dispersion of the system. In order to improve the dispersion compensation precision, the measurement is proposed. In order to suppress the random noise introduced in the phase difference image such as environment jitter and system instability, a method based on the system is proposed to measure the dispersion value and the refractive index of the transmitted sample. The phase resolution Doppler OCT technique is used to calculate the blood flow velocity in the tissue. In this method, the interference stripe signal of two consecutive A scans is removed by intercorrelation. In the flow simulation experiment, the signal to noise ratio of the velocity signal is increased from 53 dB to 56 dB; in the experiment on the blood flow imaging on the old rat ears, this method will speed up The signal-to-noise ratio of the signal is increased from 45 dB to 49 dB.. In order to solve the contradiction between the resolution of the blood flow image and the SNR of the blood flow image in the correlation imaging OCT method, it is proposed that the signal to noise ratio (SNR) of the blood flow image should be resolved. The correlation imaging OCT method based on body data is used to reconstruct the blood flow image to improve the quality of the blood flow image without reducing the image resolution in the XZ plane. The experimental results show that the signal to noise ratio of the blood flow signal obtained by the correlation imaging OCT method based on body data is 3 x 3 x 3 pixels, and the traditional correlation is compared with the window of 7 x 7 pixels. The signal to noise ratio of the blood flow signal obtained by the OCT method is 2 dB, and the resolution of the blood flow image is nearly doubled. In order to remove the jitter noise caused by the respiration and the heartbeat in the related imaging OCT method, this paper uses the technology of zero filling and image registration to register the structure image, and then extracts the blood flow by calculating the correlation coefficient. In order to improve the sensitivity of the extracted blood flow signal, we propose to use the virtual part signal in the OCT image to calculate the correlation coefficient. The experimental results show that in the blood flow image of the human skin, the technology of zero filling and image registration can effectively remove the jitter noise. In the experiment of mouse ear blood flow imaging, the method based on the virtual part can be used in the rat ear blood flow imaging experiment. More blood flow signals are extracted, including the small vascular signals that are not extracted by the traditional correlation imaging OCT method. In order to improve the quality of the blood flow image, a multi beam scanning method is proposed to suppress the noise in the blood flow image. The effects of the sample on the Doppler phase and speckle variance are analyzed and the blood is passed through the blood. The flow simulation experiment is used to verify the theory. Finally, through the human skin imaging experiment, it is proved that the multi beam scanning method can be applied to improve the quality of the blood flow image in phase resolved Doppler OCT, phase resolved Doppler variance OCT and speckle variance OCT.

【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：R445.9;TP391.41

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 陳朝良;高萬榮;廖九零;;一種用于小血流速度測量的優(yōu)化多普勒譜域光學(xué)相干層析術(shù)[J];科技導(dǎo)報(bào);2014年34期

2 陳朝良;高萬榮;;基于光譜光纖低相干的透射樣品色散和折射率測量方法[J];中國激光;2013年10期

3 李承帥;沈偉東;章岳光;范歡歡;劉旭;;基于白光干涉測量色散補(bǔ)償薄膜的群延遲色散[J];光學(xué)學(xué)報(bào);2012年10期

4 王思佳;張玉穎;胡明列;劉博文;李毅;王清月;;頻域干涉法測量光子晶體光纖的色散特性[J];中國激光;2010年01期

5 王建崗;肖青;曾紹群;;Dispersion measurements of water with spectral interferometry[J];Chinese Optics Letters;2009年06期

6 王凱;丁志華;;Spectral calibration in spectral domain optical coherence tomography[J];Chinese Optics Letters;2008年12期

7 史國華;丁志華;戴云;饒學(xué)軍;張雨東;;光纖型光學(xué)相干層析技術(shù)系統(tǒng)的眼科成像[J];中國激光;2008年09期

8 楊亞良;丁志華;孟婕;吳蘭;何梓昂;吳彤;陳明惠;;適合于內(nèi)窺成像的共路型光學(xué)相干層析成像系統(tǒng)[J];光學(xué)學(xué)報(bào);2008年05期

9 劉麗紅,劉凡光,顧瑛;光學(xué)相干層析成像術(shù)在皮膚科的應(yīng)用[J];中國激光醫(yī)學(xué)雜志;2005年05期

10 袁韜,薛平,諶一,陳煒,陳瓞延;光學(xué)相干層析成像系統(tǒng)的實(shí)驗(yàn)研究[J];光學(xué)學(xué)報(bào);1999年10期

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