Research On Focus Adjustable Probe,Compressed Sensing OCT And Its Clinical Application

Optical Coherence Tomography is an emerging imaging technology based on low coherence interferometry,which is very promising in biomedical applications.The researches in this dissertation are based on spectral domain OCT and endoscopic OCT technology,focusing on improving the imaging performance of OCT system and applying OCT in clinical applications.Some distinctive and innovative results have been demonstrated.Firstly,in terms of improving the imaging resolution of OCT,the principle of OCT determines that higher lateral resolution leads to lower depth of focus.This contradiction limits the improvement of lateral resolution.And this problem becomes more difficult to solve in an OCT endoscopic probe,because the size of an endoscopic probe is very small,and the narrow space limits the options.In this dissertation,we combine the featured hollow-core ultrasonic motor with the shape-memory-alloy spring to make a focus adjustable endoscopic probe,which is able to break the depth of focus limitation and can provide large scanning range with high resolution and si gnal-to-noise ratio.The diameter of the focus adjustable probe is only 2.5mm.Secondly,in terms of improving the image acquisition speed of OCT,as compressed sensing is applied to OCT imaging,we can get OCT images with only a small amount of data which is randomly obtained.In such case,the image acquisition speed will greatly increase.At present,the related researches in the field of compressed sensing OCT use the method of randomly throwing away some of the collected spectral data in the software a nd then performing image reconstruction.The random sampling is not realized in hardware due to the fact that the hardware random sampling is difficult to realize with the currently available devices.In this dissertation,we propose an innovative scheme t o achieve efficient hardware random sampling by adding lithography masks in the optical path.The data acquisition speed,imaging depth,and signal-to-noise ratio of the image have been improved compared with the conventional OCT system.Besides,in terms of clinical applications,OCT has many potential applications in clinical medicine,such as applications in the cardiovascular system,digestive system,and respiratory system.This dissertation introduces my research in the construction of endoscopic OCT systems for clinical imaging,including the design and fabrication of endoscopic probes,the integration of endoscopic imaging systems,the testing of system performance parameters,and the results of image acquisition in the hospital.This work has laid a good foundation for our future OCT-related clinical research,with great practical value and broad application prospects.The researches of this dissertation shows that with the development of OCT technology and the improvement of OCT performance,this te chnology will become an important biomedical imaging method,and will play an unique role in clinical diagnosis of various diseases.