The Design And Application Of The Frequency Domain-Optical Coherence Tomography System

With the demanding of imaging quality in medical imaging,in the 1990 s,Optical Coherence Tomography(OCT),an imaging technology which combines optics and computer science,have come into being as the medical imaging field.OCT is based on the basis of the theory of low-coherence interference.It can construct the tomographic image of the object in real time by analyzing the interferometric light returned from the sample and the reference arm.Besides,due to the optical imaging with the near-infrared light source,compared with CT and MRI,OCT can achieve high resolution nondestructive detection.When OCT was first proposed,it was based on Time Domain Optical Coherence Tomography(TD-OCT).Frequency-Domain Optical Coherence Tomography(FD-OCT)gradually replaced the time-domain OCT,FD-OCT is divided into Spectral Domain OCT(Spectral-Domain Optical Coherence Tomography,SD-OCT)and Frequency sweep OCT(Swept Source Optical Coherence Tomography,SS-OCT).In addition,multi-functional OCT,multi-mode OCT,and OCT imaging system combined with tissue optical clearing technology have been proposed one after another,which has obtained excellent research results in the field of medical imaging.This project mainly focuses on the construction of SD-OCT system and ss-oct system and the application of ophthalmic imaging.It mainly expands the depth of ophthalmic OCT imaging by combining the tissue optical transparency technology.The research contents and innovative achievements of this topic are listed as follows:(1)the basic theory of SD-OCT imaging was studied in detail and the structure of the system was analyzed in detail.On this basis,a SD-OCT system was designed and built,with the central wavelength of 840 nm,bandwidth of 51 nm,maximum imaging rate of 70 k Hz,longitudinal resolution of 6.1m and maximum imaging depth of 7.1mm.(2)the basic theory of SS-OCT imaging was studied in detail,and the structure of the system was analyzed in detail.On this basis,a ss-oct system was designed and built,with the central wavelength of the light source being 1310 nm,the bandwidth being 80 nm,the imaging rate being 100 k Hz,the longitudinal resolution being 9.4m,and the maximum imaging depth being 9.6mm.(3)the basic research on eye regulation theory and orbital Tissue diseases was carried out,and in combination with Tissue Optical Clearing(TOC),the posterior segment of in vitro and in vivo rabbit eyes was optically transparent.Among them,we observed the expansion effect of TOC technology on the imaging depth of OCT anterior segment through ss-oct system,providing a new measurement method for the application of OCT in the measurement of eye regulation.The imaging depth of the posterior segment of rabbit eye was obtained by SDOCT system.In the experiment,TOC was applied to the fundus of the body for the first time through the method of retrobulbar injection,and the transparent image of the posterior segment of the eye and the tissue image of the orbital tissue gap were obtained.This provides a new possibility for the diagnosis of OCT in the fundus,especially for the early diagnosis of tumors in the box.