| 何群,周堃,包尚联.一种基于峰值定位法的一阶匀场新方法[J].中国医学影像技术,2009,25(12):2290~2293 |
| 一种基于峰值定位法的一阶匀场新方法 |
| A new first order peak location shimming method |
| 投稿时间：2009-05-20 修订日期：2009-07-22 |
| DOI： |
| 中文关键词: 永磁体MRI系统 一阶匀场 峰值定位法 |
| 英文关键词:Permanent magnet MRI system First-order shimming Peak location method |
| 基金项目:973项目(2006CB705705)、国家自然科学基金(10527003、60672104)、北京市教委共建项目(JD100010607)。 |
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| 中文摘要: |
| 目的 针对永磁MR系统开发一种快速的一阶匀场方法,并在自主研发的0.5T系统上实现。 方法 对峰值定位法进行了改进,通过定量计算出涡流的影响并且用相位代替对时间的测量用于估计偏差,显著提高了测量精度。 结果 与传统方法相比,在同样匀场水平上,匀场速度提高了大约3倍,可以在小于45 s的时间获得射野内满意的主磁场均匀度。 结论 本方法可以显著改善FOV内主磁场均匀度,在短时间内完成一阶匀场,满足在0.5T永磁MR系统上进一步开发快脉冲序列的需要,并可以推广到所有永磁体的一阶匀场。 |
| 英文摘要: |
| Objective To develop a fast shimming method for permanent magnet MRI system. Methods Peak location method (PLM) was improved by calculating the eddy current effect, and the time deviation was replaced by their phase to increase the precision. Results Experiment showed that the new method took less than 45 s, which was 3 times faster than conventional method while providing the same homogeneity. The result of PLM satisfied the requirement of homogeneity. Conclusion This new method can significantly improve the homogeneity in a short time and satisfy further fast pulse sequence development on 0.5T permanent magnet MRI system, which can be generalized for any permanent magnet first order shimming. |
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