Earticle

초록

영어

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.

목차

Abstract
1. INTRODUCTION
2. DESIGN METHODOLOGY
2.1. Method for Calculating Surface Current Density of an Ideal Active Shim coil: Tikhonov regularization
2.2. Actual Shim Coil Design Process with Construction Limit Considered: Parameter Sweep Approach
3. CASE STUDY: 9.4 T WHOLE-BODY MRI ZONAL SHIM COIL DESIGN
4. DISCUSSION
5. CONCLUSION
REFERENCES

키워드

저자

• Geonyoung Kim [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ]
• Kibum Choi [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ]
• Jeonghwan Park [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ]
• Uijong Bong [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ]
• Jeseok Bang [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ] Corresponding Author
• Seungyong Hahn [ Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  한국초전도·저온논문지 (구 한국초전도저온공학회논문지) [Progress in Superconductivity and Cryogenics]

• 간기

  계간

• pISSN

  1229-3008

• eISSN

  2287-6251

• 수록기간

  1999~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 427 DDC 537