本文選題：磁聲耦合成像 + 頻域��； 參考：《北京協(xié)和醫(yī)學(xué)院》2014年博士論文

【摘要】：磁聲耦合成像是一種新型無(wú)創(chuàng)生物組織電特性功能成像技術(shù),具有超聲成像高空間分辨率和電阻抗成像高對(duì)比度的優(yōu)勢(shì),在腫瘤早期診斷方面具有重要的應(yīng)用價(jià)值。微弱聲信號(hào)的檢測(cè)和處理是磁聲成像重要的研究?jī)?nèi)容,對(duì)圖像對(duì)比度和成像精度起關(guān)鍵作用。 目前磁聲耦合成像通常采用時(shí)域的信號(hào)檢測(cè)處理方法,采用kV級(jí)高壓μs窄脈沖進(jìn)行激勵(lì)以達(dá)到mm分辨率,其激勵(lì)源設(shè)計(jì)實(shí)現(xiàn)難度較大,同時(shí)存在一定安全性問題,且時(shí)域方法檢測(cè)易受到高頻空間電磁場(chǎng)耦合干擾,限制了成像質(zhì)量。 針對(duì)目前時(shí)域磁聲耦合成像方法存在的問題,本文提出頻域的磁聲成像方法,采用kHz連續(xù)正弦信號(hào)激勵(lì),其產(chǎn)生的聲信號(hào)在kHz頻段,衰減遠(yuǎn)小于MHz頻段,簡(jiǎn)化了實(shí)驗(yàn)成像裝置。另外,頻域信號(hào)的檢測(cè)采用鎖相放大技術(shù),對(duì)微弱聲信號(hào)頻域信息的檢測(cè)放大,提高了信號(hào)檢測(cè)精度,實(shí)現(xiàn)不同頻率的信號(hào)幅值相位信息的測(cè)量,通過基于頻域檢測(cè)的圖像重建算法,實(shí)現(xiàn)組織聲源電導(dǎo)率分布圖像的重建。 本文依據(jù)波動(dòng)方程建立了頻域磁聲耦合正問題的數(shù)學(xué)模型；基于正弦波激勵(lì),采用復(fù)平面矢量疊加求和方法,對(duì)頻域磁聲耦合正問題即磁聲信號(hào)幅值相位進(jìn)行求解；并通過數(shù)值求解和解析解,對(duì)簡(jiǎn)單電導(dǎo)率邊界仿體邊界聲源進(jìn)行了仿真研究,基于復(fù)平面聲源矢量疊加方法分析了不同模型下的頻域幅值和相位特性。搭建頻域磁聲成像實(shí)驗(yàn)系統(tǒng),設(shè)計(jì)基于虛擬儀器平臺(tái)的掃描檢測(cè)系統(tǒng)的驅(qū)動(dòng)控制程序,實(shí)現(xiàn)了成像實(shí)驗(yàn)系統(tǒng)的同步驅(qū)動(dòng)控制采集和數(shù)據(jù)預(yù)處理,進(jìn)行了頻域方法的電導(dǎo)率邊界模型的實(shí)驗(yàn)研究,驗(yàn)證頻域磁聲耦合數(shù)學(xué)模型和仿真研究結(jié)果。最后建立了頻域磁聲成像逆問題模型,利用優(yōu)化算法對(duì)求解電導(dǎo)率分布的頻域磁聲耦合逆問題進(jìn)行了仿真和實(shí)驗(yàn)研究。 仿真研究表明,不同仿體的頻域幅值隨著聲源空間位置、介質(zhì)聲源幅值的變化而變化,變化規(guī)律滿足頻域磁聲耦合模型。同時(shí)對(duì)于相同介質(zhì)模型在不同頻率下,其對(duì)應(yīng)的幅值和相位不同,且多層介質(zhì)模型聲源滿足單層聲源矢量的疊加求和規(guī)則。頻域信號(hào)包含了電導(dǎo)率邊界分布信息,通過鎖相放大方法對(duì)頻域磁聲信號(hào)檢測(cè),可獲取該電導(dǎo)率信息,同時(shí)降低了激勵(lì)源的要求。實(shí)驗(yàn)結(jié)果表明,頻域相位隨距離變化規(guī)律滿足頻域磁聲耦合理論與仿真結(jié)果,對(duì)于金屬電導(dǎo)率邊界模型,輸出激勵(lì)幅值達(dá)到1V以下時(shí)即可檢測(cè)到磁聲耦合聲信號(hào)。磁聲信號(hào)的檢測(cè)精度得到提高,檢測(cè)精度可達(dá)到10-7Pa,同時(shí)空間分辨率可達(dá)到mm量級(jí)。 總之,本研究提出的頻域磁聲耦合成像方法,提高了微弱磁聲信號(hào)檢測(cè)精度,對(duì)實(shí)現(xiàn)磁聲耦合介質(zhì)內(nèi)部電導(dǎo)率的檢測(cè)和成像的研究具有重要意義。同時(shí)有利于降低磁聲耦合激勵(lì)源設(shè)計(jì)實(shí)現(xiàn)難度,簡(jiǎn)化磁聲成像系統(tǒng)系統(tǒng)設(shè)計(jì)難度,對(duì)于磁聲成像的實(shí)際應(yīng)用提供了重要基礎(chǔ)。
[Abstract]:Magnetoacoustic coupling imaging is a new type of non-invasive biological tissue electrical functional imaging technology, with the advantages of high spatial resolution ultrasound imaging and electrical impedance imaging high contrast, and has an important application value in the early diagnosis of tumor. Weak acoustic signal detection and processing is an important research content in magnetoacoustic imaging, which plays a key role in image contrast and imaging accuracy. At present, the magnetoacoustic coupling imaging usually uses the signal detection and processing method in time domain, and uses the kV high voltage 渭 s narrow pulse to excite to achieve the mm resolution. The design and realization of the excitation source is difficult, and there are some safety problems at the same time. Time domain detection is easy to be interfered by high frequency spatial electromagnetic field coupling, which limits the imaging quality. Aiming at the problems existing in the magnetoacoustic coupling imaging method in time domain, a frequency domain magnetoacoustic imaging method is proposed in this paper. The kHz continuous sinusoidal signal is used to excite the generated acoustic signal in the kHz band, and the attenuation is much less than that in the MHz band, which simplifies the experimental imaging device. In addition, the frequency domain signal is detected by phase-locked amplification technique, which amplifies the frequency domain information of weak acoustic signal, improves the signal detection precision, and realizes the measurement of amplitude and phase information of different frequency signal. The image reconstruction algorithm based on frequency domain detection is used to reconstruct the image of the conductivity distribution of the organization sound source. In this paper, the mathematical model of magnetoacoustic coupling forward problem in frequency domain is established according to the wave equation, and based on sine wave excitation, the amplitude and phase of magnetoacoustic signal are solved by using the method of superposition of complex plane vector. Numerical and analytical solutions are used to simulate the sound source with simple conductivity boundary. The amplitude and phase characteristics of different models in frequency domain are analyzed based on the method of complex plane sound source vector superposition. The frequency domain magnetoacoustic imaging experiment system is built, and the drive control program of scanning detection system based on virtual instrument platform is designed. The synchronous drive control acquisition and data preprocessing of imaging experimental system are realized. The conductivity boundary model of frequency-domain method is studied experimentally, and the results of magneto-acoustic coupling mathematical model and simulation in frequency-domain are verified. Finally, the inverse problem model of frequency-domain magnetoacoustic imaging is established, and the simulation and experiment of the frequency-domain magnetoacoustic coupling inverse problem of conductivity distribution are carried out by using the optimization algorithm. The simulation results show that the amplitudes in frequency domain vary with the spatial position of sound source and the amplitude of medium sound source, and the variation law satisfies the magnetoacoustic coupling model in frequency domain. At the same time, the amplitude and phase of the same media model are different at different frequencies, and the multi-layer media model sound source satisfies the superposition and summation rule of the single layer sound source vector. The frequency-domain signal contains the boundary distribution information of conductivity, which can be obtained by detecting the frequency-domain magnetoacoustic signal by the phase-locked amplification method, and the requirement of excitation source is reduced at the same time. The experimental results show that the frequency-domain phase variation with the distance satisfies the frequency-domain magnetoacoustic coupling theory and simulation results. For the metal conductivity boundary model, the magnetoacoustic coupling signal can be detected when the output excitation amplitude is less than 1V. The detection accuracy of magnetoacoustic signal is improved, the detection accuracy can reach 10 ~ (-7) Pa, and the spatial resolution can reach the magnitude of mm. In conclusion, the frequency domain magnetoacoustic coupling imaging method proposed in this paper improves the detection accuracy of weak magnetoacoustic signals, and is of great significance to the detection and imaging of the internal conductivity of magnetoacoustic coupling medium. At the same time, it is helpful to reduce the difficulty of design and realization of magnetoacoustic coupling excitation source and simplify the design difficulty of magnetoacoustic imaging system, which provides an important foundation for the practical application of magnetoacoustic imaging.
【學(xué)位授予單位】：北京協(xié)和醫(yī)學(xué)院
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN911.23;R730.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 安源,任超世;電阻抗斷層功能成像技術(shù)的發(fā)展[J];第四軍醫(yī)大學(xué)學(xué)報(bào);2001年01期

2 周廉;朱善安;賀斌;;三維磁感應(yīng)磁聲成像的新算法研究[J];電子學(xué)報(bào);2013年02期

3 張媛;;磁感應(yīng)磁聲成像的聲源產(chǎn)生機(jī)制[J];湖州師范學(xué)院學(xué)報(bào);2009年01期

4 馬任;殷濤;張順起;劉志朋;;基于聲換能器特性的磁感應(yīng)磁聲成像正問題分析[J];生物醫(yī)學(xué)工程與臨床;2012年03期

5 劉志朋;馬任;張順起;朱珍珍;殷濤;王延群;;磁聲耦合聲信號(hào)幅頻特性的實(shí)驗(yàn)研究[J];生物醫(yī)學(xué)工程研究;2013年01期

6 賀文靜;劉國(guó)強(qiáng);張洋;夏慧;徐路遙;李艷紅;徐小宇;曾小平;李士強(qiáng);;感應(yīng)式磁聲成像聲場(chǎng)正問題研究(一)——基于聲壓-速度耦合方程的聲場(chǎng)模擬方法[J];現(xiàn)代科學(xué)儀器;2010年01期

7 劉國(guó)強(qiáng);賀文靜;夏慧;張洋;徐路遙;李艷紅;徐小宇;曾小平;李士強(qiáng);;感應(yīng)式磁聲成像聲場(chǎng)正問題研究(二)——基于位移方程的聲場(chǎng)模擬方法[J];現(xiàn)代科學(xué)儀器;2010年01期

8 馬勇;馬青玉;章東;龔秀芬;劉曉宙;;超諧波聲場(chǎng)及其生物組織成像的理論及實(shí)驗(yàn)研究[J];聲學(xué)學(xué)報(bào);2006年05期

9 郭余慶;李宜令;馬青玉;龔秀芬;;基于聲偶極輻射的磁感應(yīng)磁聲層析成像研究[J];聲學(xué)學(xué)報(bào);2011年02期

10 楊少華,劉軍,張虹淼,樓正國(guó),李光;一種基于磁聲電相互耦合的神經(jīng)電流檢測(cè)方法[J];儀器儀表學(xué)報(bào);2005年S1期

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