面向前列腺癌诊断的聚焦式光声扫描成像原理与技术的研究

发布时间：2018-05-27 06:31

本文选题：光声成像技术 + 前列腺癌　；参考：《福建师范大学》2016年博士论文

【摘要】：光声成像技术是一种非常有前景的前列腺早期检测与成像的新技术。本论文关注长焦区聚焦式光声成像技术在前列腺癌检测中的应用,依据一种通过尿道对前列腺实施光声激发,利用外置于直肠内的长焦区聚焦式超声换能器检测光声信号的前列腺光声扫描成像技术路线,系统展开了包括前列腺光吸收分布、成像系统的构建、仿体实验及信息提取等内容的研究,取得了一些成果,论文的创新性主要包括以下几个方面：一、为理解光源内部辐照时前列腺组织中的光分布特点,指导光声成像系统构建时光源的优化选择和光声信号补偿,构建了两种弥散光源内部辐照前列腺组织的Monte Carlo模型,比较研究了其光吸收分布特点,并进一步发展为嵌肿瘤前列腺模型,开展了肿瘤光吸收差异的比较研究。二、关注不同位置的光能量时间变化关系以及光声信号产生,展开了前列腺组织光吸收时间分布的Monte Carlo模拟,利用光声信号与光吸收能量的关系,得到肿瘤附近不同位置的相对光声信号,并进行了比较分析。有关结果与实验基本一致,体现出体内光声激发在提高成像深度的优势,为前列腺光声成像系统中光声激发方式的优化选择提供了进一步的指导依据,也为将来进行模拟光声成像及提高探测准确度和光声成像深度提供了一种潜在的方法。三、根据模拟结果,给出了所提的一种新型的面向前列腺癌诊断的尿道光声激发直肠处聚焦式光声扫描成像技术的原理与方法,并在实验室现有条件下搭建了初步的光声成像实验系统,介绍了系统的硬件组成,对系统的特性做了一定的检测。最后实验表明了该成像系统具有实时监测光纤插入的能力,可用于可视化激发光源经尿道的插入过程以确保合适的光源位置。四、对柱弥散光源和侧向光纤光源两种内部激发光源分别进行了成像实验研究。首先通过设计仿体实验表明系统的成像特性,最后将成像系统成功运用到实际生物组织样品的成像实验中,并对这种光声成像技术在前列腺癌中的应用做了初步的探索,在犬的离体前列腺样品进一步得到验证。五、基于柱弥散光源的体内光辐照,提出一种吸收体光声成像和光学吸收系数同时测量的无损光声方法。通过组织内病变体吸收系数的测量,可反映出病变程度,同时结合二维扫描得到光声图像可用于病变体的定位和尺寸测量,对于前列腺肿瘤的临床监测和治疗有重要参考意义,也可应用于吸收增强的介入式肿瘤光热治疗过程。
[Abstract]:Photoacoustic imaging is a promising new technique for early detection and imaging of prostate. This paper focuses on the application of focusing photoacoustic imaging in the detection of prostate cancer, based on the photoacoustic stimulation of prostate through urethra. The light absorption distribution of prostate and the construction of imaging system were carried out by using the long focal area focused ultrasonic transducer outside the rectum to detect the photoacoustic signal of the prostate. Some achievements have been made in the research of imitation experiment and information extraction. The innovation of this paper mainly includes the following aspects: first, in order to understand the light distribution characteristics of prostate tissue when irradiated by light source, In order to guide the construction of photoacoustic imaging system, the optimal selection of light source and the compensation of photoacoustic signal were used to construct the Monte Carlo model of prostate tissue irradiated by two kinds of diffused light sources, and the characteristics of light absorption distribution were compared and studied. And further developed into the model of embedded tumor prostate, the comparative study of the difference of light absorption of tumor was carried out. Secondly, we pay attention to the relationship between the time variation of light energy and the production of photoacoustic signal at different positions, and develop the Monte Carlo simulation of light absorption time distribution of prostate tissue, using the relation between photoacoustic signal and optical absorption energy. The relative photoacoustic signals at different locations near the tumor were obtained and compared. The results are basically consistent with the experiment, which shows the superiority of photoacoustic excitation in improving the imaging depth in vivo, and provides a further guidance basis for the optimization of photoacoustic excitation mode in the prostate photoacoustic imaging system. It also provides a potential method for simulating photoacoustic imaging and improving detection accuracy and depth of photoacoustic imaging. Thirdly, according to the simulation results, the principle and method of a new type of photoacoustic scanning technique for diagnosis of prostate cancer, which is focused on the rectum of urethra photoacoustic excitation, is presented. A preliminary photoacoustic imaging experimental system is built under the existing conditions in the laboratory. The hardware composition of the system is introduced, and the characteristics of the system are tested to a certain extent. Finally, the experimental results show that the imaging system can monitor the insertion of optical fiber in real time and can be used to visualize the transurethral insertion of the excited light source to ensure the proper position of the light source. Fourth, two kinds of internal excitation light sources, column dispersion light source and lateral fiber source, are studied by imaging experiments. At first, the imaging characteristics of the system are demonstrated by designing the phantom experiment. Finally, the imaging system is successfully applied to the imaging experiment of the actual biological tissue sample, and the application of this photoacoustic imaging technology in prostate cancer is explored. Samples of isolated prostate in dogs were further verified. Fifth, a nondestructive photoacoustic method for simultaneous measurement of absorber photoacoustic imaging and optical absorption coefficient is proposed. The degree of the lesion can be reflected by the measurement of the absorption coefficient of the lesion in the tissue, and the photoacoustic image can be used to locate and measure the size of the lesion, which is of great significance for the clinical monitoring and treatment of prostate tumor. It can also be used in absorption-enhanced photothermal therapy of interventional tumor.
【学位授予单位】：福建师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R737.25;R730.4

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