基于圆周扫描的内窥式频域检测系统及成像实验研究

发布时间：2018-03-28 15:08

本文选题：近红外漫射光成像　切入点：频域外差　出处：《天津大学》2012年硕士论文

【摘要】：内窥式近红外漫射光成像技术是一种可用于内部器官癌症检测的新型光学测量技术，因其具有实时、无创的特点在癌症的早期诊断方面发挥着重要作用。为了有效的实现对早期宫颈癌的检测，本文在原有频域系统的基础上，建立了基于有效探测区理论（Effective Detection Range，EDR）的内窥式圆周扫描成像系统。首先，为了实现基于EDR的内窥检测，设计了一种新型的内窥式旋转探头，仅用一根源光纤和一根探测光纤即可实现圆周扫描成像，简化了系统并降低成本。并利用蒙特卡洛模拟对光纤参数的选择提供理论指导。为了实现光垂直照射到宫颈内壁并垂直接收，探头的源光纤顶端加上一端切成45°斜面的自聚焦透镜，对光实现准直和偏折90°的作用，探测光纤直接将光纤顶端切成45°斜面，用于接收垂直于组织体壁的光。内窥探头的旋转精度的实验结果表明：源光纤对于幅值和相位的测量的最大相对误差分别是1.7%和0.13%，探测光纤的最大相对误差分别是3.01%和0.58%。其次，为了实现频域系统的自动化控制，本文在LabVIEW平台下，将内窥旋转探头和频域系统结合进行软件集成，，从而节省人力和时间。并在不同的源探距离下验证了基于内窥探头频域系统的精度，实验结果表明，该系统测量幅值和相位相对误差分别为12.3%和20.9%，另外，针对上述结果，本文对系统可能存在的误差原因及改进措施进行了分析和阐述。最后，在上述内窥式频域系统的基础上，本文分别利用固体仿体和仿宫颈组织对系统的成像能力进行了验证。在固体仿体实验中，分别对单目标仿体和双目标仿体的异质体进行了重构实验，结果表明：重构的目标体的位置和大小和实际的目标体基本一致，双异质体可被清晰分开，吸收和约化散射系数的量化度（Quantitative Ratio，QR）分别可达到25%和20%以上。仿宫颈组织的实验结果表明：重构异质体的位置正确，且重构出的吸收系数和约化散射系数的QR值分别可达到25.3%和18.7%。综上所述，基于EDR的内窥式圆周扫描成像系统可获得合理的成像质量，为临床实验的实施打下了坚实基础。
[Abstract]:Endoscopic near-infrared diffuse light imaging (NIR) is a new optical measurement technique that can be used to detect cancer in internal organs because of its real time. Non-invasive features play an important role in the early diagnosis of cancer. In order to effectively detect early cervical cancer, this paper is based on the original frequency domain system. An endoscopic circumferential scanning imaging system based on effective Detection (EDR) is established. First of all, in order to realize endoscope detection based on EDR, a new type of endoscope rotary probe is designed, which can realize circumferential scanning imaging with only one source fiber and one detecting fiber. It simplifies the system and reduces the cost. Monte Carlo simulation is used to provide theoretical guidance on the choice of optical fiber parameters. In order to achieve vertical light exposure to the inner wall of the cervix and vertical reception, The probe has a self-focusing lens cut into 45 掳sloping plane at one end of the source optical fiber, which can collimate and deflect the light by 90 掳. The probe fiber directly cuts the top of the fiber into 45 掳oblique plane. The experimental results show that the maximum relative errors for the measurement of amplitude and phase of the source fiber are 1.7% and 0.13%, respectively, and the maximum relative errors for the probe are 3.01% and 0.58 respectively. Secondly, in order to realize the automatic control of the frequency domain system, this paper integrates the endoscope rotation probe and the frequency domain system under the LabVIEW platform to carry on the software integration. The precision of frequency domain system based on endoscope probe is verified under different source range. The experimental results show that the relative errors of amplitude and phase of the system are 12.3% and 20.9%, respectively. In addition, in view of the above results, In this paper, the possible error causes and improvement measures of the system are analyzed and expounded. Finally, on the basis of the frequency domain system of endoscope, the imaging ability of the system is verified by solid imitating body and cervical tissue, respectively. Experiments were carried out on the homogeneity of single target and double target respectively. The results show that the position and size of the reconstructed object are basically the same as the actual object, and the double heterogeneity can be clearly separated. The quantification of absorption and reductive scattering coefficients can reach more than 25% and 20% respectively. The QR values of the reconstructed absorption coefficient and reduced scattering coefficient can reach 25.3% and 18.7% respectively. In conclusion, the endoscopic circumferential scanning imaging system based on EDR can obtain reasonable imaging quality and lay a solid foundation for clinical experiment.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R310

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