Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
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A simulation-based design study of superconducting zonal shim coil for a 9.4 T whole-body MRI magnet

  • Kim, Geonyoung (Department of Electrical and Computer Engineering, Seoul National University) ;
  • Choi, Kibum (Department of Electrical and Computer Engineering, Seoul National University) ;
  • Park, Jeonghwan (Department of Electrical and Computer Engineering, Seoul National University) ;
  • Bong, Uijong (Department of Electrical and Computer Engineering, Seoul National University) ;
  • Bang, Jeseok (Department of Electrical and Computer Engineering, Seoul National University) ;
  • Hahn, Seungyong (Department of Electrical and Computer Engineering, Seoul National University)
  • Received : 2020.03.06
  • Accepted : 2020.03.30
  • Published : 2020.03.31
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Abstract

As high homogeneity in magnetic field is required to increase the resolution of MRI magnets, various shimming methods have been researched. Using one of them, the design of the superconducting active zonal shim coil for MRI magnets is discussed in this paper. The magnetic field of the MRI magnet is expressed as the sum of spherical harmonic terms, and the optimized current density of shim coils capable of removing higher-order terms is calculated by the Tikhonov regularization method. To investigate all potential designs derived from calculated current density, 4 sweeping parameters are selected: (1) axial length of shim coil zone; (2) radius of shim coils; (3) exact axial position of shim coils; and (4) operating current. After adequate designs are determined with constraints of critical current margin and homogeneity criterion, the total wire length required for each is calculated and the design with a minimum of them is chosen. Using the superconducting wire length of 9.77 km, the field homogeneity over 50 cm DSV is improved from 24 ppm to 1.87 ppm in the case study for 9.4 T whole-body MRI shimming. Finally, the results are compared with the finite element method (FEM) simulation results to validate the feasibility and accuracy of the design.

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References

  1. H. Miyazaki, S. Iwai, Y. Otani, M. Takahashi, T. Tosaka, K. Tasaki, S. Nomura, T. Kurusu, H. Ueda, S. Noguchi, A. Ishiyama, S. Uraama, and H. Fukuyama, "Design of a conduction-cooled 9.4T REBCO magnet for whole-body MRI systems," Supercond. Sci. Technol. 29, 104001, 2016
  2. Y. Dai, Q. Wang, C. Wang, L. Li, H. Wang, Z. Ni, S. Song, S. Chen, B. Zhao, H. Wang, Y. Li, X. Hu, C. Cui, J. Cheng, Y. Lei, and L. Yan, "Structural Design of a 9.4 T Whole-Body MRI Superconducting Magnet," IEEE Trans. Appl. Supercond., vol. 22, no. 3, 4900404, June, 2012
  3. J. J. Du, P. Yuan, W. Wu, L. Z. Ma, and X. L. Yang, "Active Shim Design of a 7 T Highly Homogeneous Superconducting Magnet for Lanzhou Penning Trap," IEEE Trans. Appl. Supercond., vol. 22, no. 3, 4902004, June, 2012
  4. D. I. Hoult and R. Deslauriers, "Accurate Shim-Coil Design and Magnet-Field Profiling by a Power-Minimization-Matrix Method," J. Magn. Reson., Series A 180, pp.9-20, 1994
  5. C. Juchem, B. Muller-Bierl, F. Schick, N. K. Logothetis, and J. Prfeuffer, "Combined passive and active shimming for in vivo MR spectroscopy at high magnetic fields," J. Magn. Reson., 183, pp.278-289, 2006 https://doi.org/10.1016/j.jmr.2006.09.002
  6. R. Vadovic, "Magnetic Field Correction Using Magnetized Shims," IEEE Trans. Magn., vol. 25, no. 4, pp.3133-3139, 1989 https://doi.org/10.1109/20.34386
  7. L. K. Forbes, M. A. Brideson, and S. Crozier, "A Target-Field Method to Design Circular Biplanar Coils for Asymmetric Shim and Gradient Fields," IEEE Trans. Magn., vol. 41, no. 6, pp.2134-2144, 2005 https://doi.org/10.1109/TMAG.2005.847638
  8. H. S. Lopez, F. Liu, E. Weber, and S. Crozier, "Passive Shim Design and a Shimming Approach for Biplanar Permanent Magnetic Resonance Imaging Magnets," IEEE Trans. Magn., vol. 44, no. 3, pp.394-402, 2008 https://doi.org/10.1109/TMAG.2007.914770
  9. S. Hahn, M. Ahn, J. Bascunan, W. Yao, and Y. Iwasa, "Nonlinear Behavior of a Shim Coil in an LTS/HTS NMR Magnet With an HTS Insert Comprising Double-Pancake HTS-Tape Coils," IEEE Trans. Appl. Supercond., vol. 19, no. 3, pp.2285-2288, June, 2009 https://doi.org/10.1109/TASC.2009.2018809
  10. G. Hu, Z. Ni, and Q. Wang, "A Novel Target-Field Method Using LASSO Algorithm for Shim and Gradient Coil Design," IEEE Trans. Appl. Supercond., vol. 22, no. 3, 4900604, June, 2012
  11. G. Hu, Z. Ni, and Q. Wang, "Shim Coil Set for NMR Using a Novel Target Field Method Based on Trigonometric Series," IEEE Trans. Appl. Supercond., vol. 24, no. 3, 4302105, June, 2014
  12. M. Weiger and T. Speck, "Shimming for high-resolution NMR spectroscopy," eMagRes., pp.4468-4486, 2011
  13. P. Hudson, S. D. Hudson, W. B. Handler, and B. A. Chronik, "Finite-Length Shim Coil Design Using a Fourier Series Minimum Inductance and Minimum Power Algorithm," Concepts Magn. Reson. Part B. 37, pp.245-253, 2010
  14. M. Ahn, S. Hahn, and H. Lee, "3-D Field Mapping and Active Shimming of a Screening-Current-Induced Field in an HTS Coil Using Harmonic Analysis for High-Resolution NMR Magnets," IEEE Trans. Appl. Supercond., vol. 23, no. 3, 4400804, June, 2013
  15. S. Chen, T. Xia, Z. Miao, L. Xu, H. Wang, and S. Dai, "Active shimming method for a 21.3 MHz small-animal MRI magnet," Meas. Sci. Technol. 28, 055902, 2017
  16. J. Du, P. Yuan, L. Ma, W. Wu, and X. Yang, "A novel design methodology for active shim coil," Meas. Sci. Technol. 23, 085502, 2012
  17. P. Konzbul and K. Sveda, "Shim coils for NMR and MRI solenoid magnets," Meas. Sci. Technol. 6, pp.1116-1123, 1995 https://doi.org/10.1088/0957-0233/6/8/005
  18. Z. Ni, L. Li, G. Hu, X. Hu, F. Liu, and Q. Wang, "Design of Superconducting Shim Coils for a 400 MHz NMR Using Nonlinear Optimization Algorithm," IEEE Trans. Appl. Supercond., vol. 22, no. 3, 4900505, June, 2012
  19. S. Iguchi, Y. Yanagisawa, M. Takahashi, T. Takao, K. Hashi, S. Ohki, G. Nishijima, S. Matsumoto, T. Noguchi, R. Tanaka, H. Suematsu, K. Saito, and T. Shimizu, "Shimming for the 1020 MHz LTS/Bi-2223 NMR Magnet," IEEE Trans. Appl. Supercond., vol. 26, no. 4, 4303507, June, 2016
  20. X. Zhu, Q. Wang, Y. Li, Y. Hu, W. Chen, and F. Liu, "The Design of Decoupled Even-Order Zonal Superconducting Shim Coils for a 9.4 T Whole-Body MRI," IEEE Trans. Appl. Supercond., vol. 26, no. 8, 4403708, December, 2016
  21. C. Niu, X. Zhu, Q. Wang, Y. Li, F. Tang, and F. Liu, "A Novel Design Method of Independent Zonal Superconducting Shim Coil," IEEE Trans. Appl. Supercond., vol. 29, no. 1, 4400108, December, 2019
  22. S. Iguchi, R. Piao, M. Hamada, S. Matsumoto, H. Suematsu, T. Takao, J. Li, X. Jin, M. Takahashi, H. Maeda, and Y. Yanagisawa, "Advanced field shimming technology to reduce the influence of a screening current in a REBCO coil for a high-resolution NMR magnet," Supercond. Sci. Technol. vol. 29, 045013, 2016
  23. L. K. Forbes and S. Crozier, "A novel target-field method for finite-length magnetic resonance shim coils: I. Zonal shims," J. Phys. D: Appl. Phys. 34, pp.3447-3455, 2001 https://doi.org/10.1088/0022-3727/34/24/305
  24. L. K. Forbes and S. Crozier, "A novel target-field method for finite-length magnetic resonance shim coils: II. Tesseral shims," J. Phys. D: Appl. Phys. 35, pp.839-849, 2002 https://doi.org/10.1088/0022-3727/35/9/303
  25. B. J. Parkinson, R. Slade, M. J. D. Mallett, and V. Chamritski, "Development of a Cryogen Free 1.5 T YBCO HTS Magnet for MRI," IEEE Trans. Appl. Supercond., vol. 23, no. 3, 4400405, June, 2013
  26. G. D. Brittles, T. Mousavi, C. R. M. Grovenor, C. Aksoy, and S. C. Speller, "Persistent current joints between technological superconductors," Supercond. Sci. Technol. vol. 28, 093001, 2015
  27. H. Miao, K. R. Marken, M. Meinesz, B. Czabaj, and S. Hong, "Development of Round Multifilament Bi-2212/Ag Wires for High Field Magnet Applications," IEEE Trans. Appl. Supercond., vol. 15, no. 2, pp.2554-2557, June, 2005 https://doi.org/10.1109/TASC.2005.847648
  28. H. Miao, K. R. Marken, M. Meinesz, B. Czabaj, S. Hong, A. Twin, P. Noonan, U. P. Trociewitz, and J. Schwartz, "High Field Insert Coils from Bi-2212/Ag Round Wires," IEEE Trans. Appl. Supercond., vol. 17, no. 2, June, 2007