The Design Of Acquisition And Control System For Micro-CT Based On FPGA

The rapid development of medical imaging technology has brought good news to all patients.The disease can be diagnosed and treated without suffering the pain and risk of clinical surgery.As a technique for obtaining precise anatomical images,Computed tomography plays an indispensable role in the development of medical images.Besides,the small animal medical models have become an important part for human disease research.Most human diseases can be modeled on animals to find treatment methods.However,the spatial resolution of common clinical CT equipment cannot meet the requirement of small animal imaging,which hinders the development of the small animal medical model.Therefore,Micro-CT equipment with higher spatial resolution and faster reconstruction algorithm is urgently needed.It not only accelerates the development of small animal medical models,but also drives the emergence of multimodal molecular images.Based on the research of multi-modal molecular imaging in the research group,this thesis designed a set of FPGA-based Micro-CT acquisition control system.The system uses micro-focus X-ray source and high-performance flat panel detector to achieve synchronous control of X-ray source,detector and motion controller in two acquisition modes,and undertakes the task of real-time information exchange with the host computer.This system is used for tomography of small animal,which can obtain clearer internal information,and has good accuracy,real-time and stability.The main research work of this thesis includes the following aspects:(1)By investigating the existing Micro-CT in the market,the core components of the system were selected,such as X-ray source,detector and motion control components.Then the basic working principles of the core components were introduced.Through comparison and analysis,the models of the core components were determined.(2)The design scheme of Micro-CT system scanner frame was determined.The panel structure and the rotating frame of micro-CT system were designed and modeled by Solidworks.The magnification and spatial resolution of the system were calculated in detail.The depth of X-ray penetration,the rationality of the frame structure and the bearing load capacity were verified.(3)The hardware and software of Micro-CT acquisition and control system were developed by using FPGA as the main control chip.After the analysis of hardware requirements and the selection of FPGA,the system circuit was designed,and the PCB board layout and testing were carried out.Then the software core and peripheral IP were built inside the FPGA,and the system control program and hardware logic were developed,including the acquisition mode of the system and the communication of host computer.Finally,simulation verification and test evaluation were carried out according to the designed hardware logic module.(4)This part introduced briefly the reconstruction model and algorithm for the system equipment,and summarized the characteristics of the developed system according to the system design and the actual machine operation.Finally set up a series of parameters operation system on the host computer to carry out in vivo experiments on mice.The results verified the feasibility and application performance of the system.