开放式永磁机构无源匀场方法  

Passive Shimming Method for Open Permanent Magnet Structure

作　　者：张艳丽[1] 谢德馨[1] 王恩龙[1] 曾林锁[1] 白保东[1] 

机构地区：[1]沈阳工业大学电气工程学院,沈阳110023

出　　处：《电工技术学报》2007年第6期1-5,共5页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(50377027);教育部高等学校博士学科点专项科研基金(20050142003)资助项目。

摘　　要：针对永磁磁共振成像磁体系统无源匀场技术面临的困难,提出了无源匀场的整数规划优化方法。在无源匀场优化模型建立过程中,采用实测法来获得单位垫片对基础磁场的影响,并利用磁性垫片产生的磁场来弥补各测试点的磁场偏差。该方法避免了解析求解磁性垫片产生磁场过程中所遇到的困难。通过对优化模型的求解获得匀场信息,实现计算机匀场,从而提高匀场的工作效率。为了验证所提出的匀场方法的正确性,在0.3T永磁磁共振成像磁体系统上进行了实验研究,实验结果充分证明了所提出的匀场方法的有效性。To solve the difficult problem of the passive shimming for the magnetic resonance imaging （MRI） system with permanent magnet, a new passive shimming method named integer programming （IP） based on an optimum algorithm is presented in the paper, in which the influence of the shimming block on the magnetic field is obtained by actual measurement and the optimum objective is to make the magnetic field error at the measured points in the imaging region minimum. The proposed approach can avoid the difficulty in finding the influence of the shimming block on the magnetic field obtained by analytical method and raise the efficiency of the shimming. The computer simulation and experiments are carried out on a 0.3T MRI system with permanent magnet. The experimental results show that the shimming algorithmis feasible.

关 键 词：磁体系统 整数规划 无源匀场 磁共振成像 

分 类 号：TM153[电气工程—电工理论与新技术]