Design And Application Research Of High Resolution X-ray RF Digital Imaging System

X-ray digital gastro intestine diagnosis system, a modern medical diagnosis method, is applied to digital sampling, digital procession, digital storing, and digital transmission of gastro intestine images. Therefore the management without films and image sharing are realized to facilitate patients'images diagnosis and patients'documents communication. X-ray digital gastro intestine imaging system is the core subsystem of this system, by which the dynamic examination and real-time diagnosis of pathological changes of alimentary canal organs is performed. By now, X-ray digital gastro intestine imaging systems are principally based on intensifier and CCD system, the resolution of which is mostly 1024×1024. High-end imaging products are monopolized by foreign international manufacturers, e.g. Siemens, Philip, GE, Toshiba, Hitachi, etc. Clavis2000 image system of Hitachi medical Corp. in Japan take a leading role in this field, by which the 2k*2k*12Bit X-ray digital images of gastro intestine is obtained.This thesis aims to trace overseas latest techniques and to design a prototype, and to propose the design principle and approach of X-ray digital gastro intestine CCD imaging system with technique index of 2048*2048*12Bit. Many fundamental problems and engineering problems of imaging techniques are involved in this system, including basic characteristics of X-ray, interaction between X-ray and materials, attenuation law of X-ray penetrating human body, the effect of X-ray channel on image qualities, the principle of imaging intensifier, the working principle of CCD digital camera, DICOM transmission and structures of equipment, the basic principle of imaging, etc. On the basis of studying and analyzing these problems, the holistic structure design, system function design, engineering-related hardware and software design of X-ray digital gastro intestine imaging system are performed in this thesis. It also deals with how to choose digital CCD camera and grabber board, how to choose camera lens and design optical channel, how to design doctor's operation flow, and how to process, transmit and print digital images. The engineering system design problems are investigated,such as the method of dynamically real-time reducing noise, real-time control of brightness and X-ray dose to ensure best images acquisition quality. The synchronous acquisition interface of X-ray high voltage generator is deeply studied and analyzed. In relevant hospital, engineering test is carried out for this designed X-ray digital gastro intestine imaging systems, and the resolution is as high as 2.8lp/mm, which proves that it is superior to similar products home and abroad. The clinic application is to perform experiment on items such as esophagus examination, upper digestive tract examination, whole digestive tract examination, hysterosalpinggography and intravenous pyelography. Meanwhile, some special functions are also testified, e.g. fast spot radiograph. Through clinical application verification, by dynamic real-time multi-rate fast spot radiograph, the images of transient motion of swallow action can be acquired real time dynamically, which solves the problem that doctors can hardly grasp the best timing of filming swallow and peristalsis. In addition, the real-time digital subtraction angiography provides images with more exquisite quality, and this system has good value for clinical extension and application.