摘要
为了符合成像标准,磁共振成像(MRI)设备要求主磁体能在较大的成像空间内产生高均匀度的磁场。但由于加工误差,实际磁场的均匀度远不能达到预定的要求,需要采用特殊方法进行匀场。本研究提出一种基于整数规划算法的无源匀场方法,将磁体的匀场问题提炼为整数规划问题,并编制了相应的匀场软件。通过在磁共振主磁体生产厂家进行的无源匀场实验,使得磁场的不均匀度从1549.7898×10-6降低到1129.9105×10-6,即均匀度提高了27%,证明该方法在一定程度上能够快速、有效地完成匀场过程,提高磁场的均匀度。
In order to match the imaging standard, the Magnetic Resonance Imaging （MRI） device requires high field homogeneity in a large imaging region. Owing to the manufacturing tolerances that reduce the field homogeneity, some pest-manufacturing field corrections are required to bring the magnetic field uniformities to an acceptable level. Based on integer programming algorithm and basic theories of shimming, a new passive shimming method was proposed. The results showed that the un-uniformity was reduced from 1549.7898 × 10^-6 to 1129.9105 × 10^-6 by experiments of shimming in the MRI devices manufactory, meaning that the uniformity increased by 27%. The proposed method is effective and fast in improving the field uniformity of the imaging region at a certain extent.
出处
《中国生物医学工程学报》
CAS
CSCD
北大核心
2008年第4期533-536,共4页
Chinese Journal of Biomedical Engineering
基金
高等学校博士学科点专项科研基金资助项目(20050142003)
关键词
磁共振成像
均匀度
整数规划
无源匀场
magnetic resonance imaging （MRI）
homogeneity
integer programming
passive shimming
