A SQP optimization method for shimming a permanent MRI magnet

作者：Jin Zhe; Tang Xing; Meng Bin; Zu Donglin; Wang Weimin^*

来源：Progress in Natural Science, 2009, 19(10): 1439-1443.

DOI：10.1016/j.pnsc.2009.04.007

• Magnetic resonance imaging (MRI)
• Field shimming
• Sequential quadratic programming (SQP)
• Permanent MRI magnet

Based on the sequential quadratic programming (SQP) method, a new approach is presented in this paper to gain a uniform magnetic field for a permanent MRI magnet with biplanar poles. First, the adopted shimming piece is modeled as a magnetic dipole moment to calculate its effect on the background field over the imaging region of interest. Then, the SQP method is utilized to determine the ideal solution for the shimming equation. Finally, the ideal solution is discrete, and the quantization error control technique is used for special cases. This new method helps to reduce the inhomogeneity from 1234.5 ppm to 21.4 ppm over a 36 cm diameter spherical volume (DSV), within hours in practical shimming work.

• 出版日期2009-10-10
• 单位北京大学