光纤结构的共臂分光OCT内窥镜在癌症早期诊断中的研究

Cancer is a type of grave disease which seriously menaces the health of the human beings, and earlier diagnosis of cancer is the most effective treatment for raising the recovered rate. Due to the small volume of incipient tumors, the conventional imaging methods cannot effectively diagnose early-stage cancer. Since the spatial resolution of optical coherence tomography (OCT) can reach the magnitude of micron, and if the OCT probe possesses the characteristic of small fabric and nice flexibility in order to easily enter into human body, OCT probe can detect the tumors in a very early-stage. So, this proposal mainly research on: 1) Modeling of fiber structure common-path endoscopic OCT (CP-EOCT). By using a fiber collimator and a glass tube as beam-splitting Michelson interferometer, an ultracompact CP-EOCT probe is designed to achieve the combined goals of high spatial resolution, small volume and flexibility. Moreover, compared with conventional EOCT, This probe has great advantage of high phase stability because the common-path structure will not be affected by the gastrointestinal peristalsis and blood flow when enter into human body. 2) Scanning mechanism of CP-EOCT system. Rotors, stators and clutches are employed to separate A-Scan and B-Scan in the condition of common-path, and in the meanwhile, to adjust the working distance of CP-EOCT probe. 3) Two frames phase-shifting algorithm with the step of OCT resolution. This algorithm significantly lowers the demand for the accuracy of phase shifter, which attains the goals of simplifying phase-shift device and reducing cost.

癌症一直严重威胁着人类的健康和生命，癌症的早期诊断是提高治愈率的最有效方法。由于早期肿瘤体积微小，当前影像学方法并不能有效诊断。光学相干层析(OCT)技术可达到微米级分辨率，如能制作微小且柔度好的OCT探针进入人体内，则癌细胞在微米级变异时就可做出诊断。为此将重点研究：1)光纤结构的共臂分光OCT内窥镜系统建模。通过一特殊的光纤准直器，并通过一个中空毛细玻璃管实现共臂分光，使整个共臂OCT内窥镜为光纤尺寸大小，达到减小设备体积、增加柔度的目的。此方法可以解决传统OCT内窥镜的信号臂在人体内时，因肠道蠕动和血液流动等因素，信号臂相对于参考臂处于不稳定状态的问题；2) 研究一种适合此共臂分光系统的三维扫描机构。通过引入转子、定子及离合器机构，在共臂前提下分别实现横向扫面和轴向扫描；3)以OCT轴向分辨率为步长的两帧相移算法。该算法对相移器的移动精度要求大为降低，从而简化相移机构，降低成本。

以减小整个OCT系统的体积、增加OCT系统的柔度为目的，研究了一种基于全光纤结构的共臂分光OCT内窥镜系统。完成了超小光纤探测设计的共臂OCT 系统建模。通过一特殊的光纤准直器，并通过一个表面镀银的光学玻璃棒实现共臂分光，并虚拟出参考面，从而减小整个共臂OCT 探针的尺寸；研究了一种适合此共臂分光系统的三维扫描机构。通过引入转子、定子及离合器机构，在共臂前提下分别实现横向扫面和轴向扫描；建立了一种非可见的红外相干光的共臂分光OCT系统光路调整方案；为实现光路准直并将全光纤结构引入共臂分光OCT系统，结合非线性梯度多模光纤的传光特性及OCT系统的原理，研究了一种全光纤准直器，构建并完成了整个光纤准直器的制作过程；结合共臂分光OCT系统的原理和研究基础，合作研究了一种基于全光纤结构的光子晶体光纤张力传感器；实现了毛细玻璃管和光纤的多种熔接方式，研究了光在毛细玻璃管中的传输性质，研究了毛细玻璃管与光纤在普通焊接模式和角锥焊接模式下光的传输原理和性质，并实现了将高温液体和机油等泵入毛细玻璃管的方法，从而达到改变毛细玻璃管真空管芯折射率的目的；最后，研究了一种基于微小光纤结构的频域OCT系统的傅立叶算法。