Research On Optimization Design Of MRI System Based On ANSYS

Magnetic Resonance Imaging (MRI) apparatus is a high-technology product that integrates the magnet manufacturing technology, electronic technology and computer technology. It can be divided into resistive, permanent magnetic and superconducting according to the mechanism of how to evolve the magnetic field. The superconducting magnet is used in high field, Others are used in low or medium field.Compared to X -rays CT, the most superior of MRI is no radiation, that is to say, no direct injury to human body. Secondly, the image contrast of soft tissue is better than CT. MRI can detect the metabolism of cells in biotic tissue, which can be applied in functional imaging. Thirdly, the location of MRI is by means of adjusting magnetic field. The selection of section is more flexible than CT. Because of the development of fast pulse sequence such as EPI and EVI, and new method of FFT used in image reconstruction, the time in MRI is rapidly come down. MRI becomes one of the most important, most valuable and most prospected medical diagnostic method.Because MRI is used in functional imaging and interventional therapy in recent years, the open magnet is applied in MRI apparatus Another superiority of open environment is that it can check cavernfrightened patients, infants and some animals. After the comprehension of this newest international trend, the author did some initiated theoretical and practical works.This Master Assignment will contribute an overall conclusion, which base on the designing of superconducting MRI main magnet by the principle of sixth-phase coil. The main objects which it relates to : Basic introduction of NMR, Main component of MRI equipment and its imaging process; followed by the introduction of magnet technique, the critical part is the method of designing the main magnet of superconducting MRI; then I will spend more time on introduction of engineering design of 0.5T superconducting MRI system whose main magnet is like solenoid, which contents the following area: the blueprint of main magnet system, simulation for the magnet based on Finite Element Method and specifically talk about computer based software related to the design of magnet system, shimming theory and the development process of design. At the end, this assignment will also give a conclusion, personal understanding and suggestion based on above material.According to the comparison of the result from simulation and theoretical calculating, to prove the design of main magnet system is adequate, the computing and design software is reliable, the theory of no shielding shimming is viable.