高分辨与变焦内窥光学相干CT研究

发布时间：2017-12-28 17:25

本文关键词：高分辨与变焦内窥光学相干CT研究　出处：《清华大学》2016年博士论文　论文类型：学位论文

【摘要】：光学相干层析成像(Optical coherence tomography,OCT)是基于相干光干涉测量的一种新型三维成像技术,该技术因为具有非侵入、低损伤、深度测量、高分辩等特点,已被广泛应用于生物医学领域。内窥光学相干层析(Endoscopic optical coherence tomography,E-OCT),与内窥技术相结合,通过光纤可将光引导到活体的各个部位,克服了光的穿透深度有限的缺点,可在人体不同部位成像,大大提高了在临床的应用价值,尤其是高分辨OCT,有望替代活检,在癌症肿瘤检测方面,具有重要的应用前景。本文以内窥相干层析技术为基础,结合微机电与光学技术,取得了如下结果:首先,在内窥OCT领域,传统的电机集成的侧向扫描探头在实现高转速的同时,往往无法保证高分辨率(10μm),成像无遮挡以及体积小(2mm)的三者兼顾,该问题制约了内窥OCT探头在临床的进一步研究,成为了实际运用中的瓶颈。本文提出了结合非球面棱镜与1.0mm中空超声电机的高性能探头设计,通过改善成像光路,系统性能与光斑质量,实现了7.5μm×6.6μm的高分辨,360度无盲区的内窥成像,其封装后外径可以缩小至1.4mm,有效提高了整体参数性能。实验证明了该高性能探头方案的可行性,预示其良好的临床应用前景。其次,本文详尽分析了高分辨OCT领域中普遍存在的分辨率-焦深制约问题,和各种已有的解决方案,结合内窥技术领域的实际问题,运用光学模拟设计手段,提出了自加热记忆合金材料结合中空电机的结构,以实现可调节的末端光路与变焦效果,通过多次成像克服焦深的制约,从而改善高分辨内窥情形下的成像质量。在实验上成功研制了世界首个具有变焦机能的高性能内窥OCT原型探头,并进行了成像实验以验证效果。此外,考虑到内窥技术的精细和复杂性,本文对内置微型电机的探头设计要点和原型组装的主要步骤做了系统归纳与总结,并在附录中记录了探头各零部件的制作工艺。综上,本论文研制成功高分辨与变焦内窥OCT探头,结合OCT成像系统,可以为临床诊断提供高分辨率、无创的三维断层扫描图像,有利于病灶原位的实时监测,在重大疾病的早期检测方面,将发挥重要的作用。
[Abstract]:Optical coherence tomography (OCT) is a new 3D imaging technology based on coherent light interference measurement. Because of its characteristics of non-invasive, low damage, deep measurement and high resolution, it has been widely applied in biomedical field. Endoscopic optical coherence tomography (Endoscopic optical coherence tomography E-OCT) technology, combined with endoscope, through the optical fiber light can be guided to all parts of the living body, overcomes the disadvantages of limited light penetration depth, imaging in the different parts of the body, greatly improving the clinical value, especially high resolution OCT that is expected to replace biopsy in cancer detection has important application prospect. In this paper, endoscopic optical coherence tomography technology, combining MEMS and optical technology, the main results are as follows: firstly, the endoscopic OCT field, the traditional motor integrated lateral scanning probe used in high speed at the same time, often can not guarantee the high resolution (10 m), and small volume imaging without occlusion (2mm). The three consideration, the problem of restricting the endoscopic OCT probe in further clinical research, become a bottleneck in practical application. This paper combines high performance probe design of aspheric prism and 1.0mm hollow ultrasonic motor, by improving the imaging optical path, system performance and spot quality, achieve m 7.5 * 6.6 m high resolution, 360 non blind endoscopic imaging, the package diameter can be reduced to 1.4mm, effectively improve the the overall performance parameters. The experiment proves the feasibility of the high performance probe and indicates the good prospect of clinical application. Secondly, this paper detailed analysis of the high resolution OCT is existed in the field of resolution - focal depth constraints, solutions and various existing problems, combined with endoscopic technology, using optical simulation design method, put forward the self heating with memory alloy material structure of hollow motor, the end of the light path and the zoom effect to achieve the adjustable, overcome the constraints of focal depth by multiple imaging, so as to improve the image quality of high resolution under endoscope. In the experiment, the first high performance endoscope OCT prototype with a zoom function was successfully developed, and the imaging experiment was carried out to verify the effect. Besides, considering the precision and complexity of the endoscopic technology, the design points and the main steps of the prototype assembly of the built-in micro motor are systematically summarized and summarized, and the manufacturing process of each part of the probe is recorded in the appendix. In summary, this paper successfully developed high resolution zoom endoscope and OCT probe combined with OCT imaging system, 3D images can provide high-resolution, noninvasive clinical diagnosis, real-time monitoring for in situ lesions, in the early detection of major diseases, will play an important role.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R318;TP391.41

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