Journal of the Institute of Electronics Engineers of Korea SC (전자공학회논문지SC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Development of an Active Magnetic Noise Shielding System for a Permanent Magnet Based MRI

영구자석 MRI를 위한 능동형 자기 잡음 차폐시스템 기술 개발

  • 이수열 (경희대학교 동서의학대학원 의료공학전공) ;
  • 전인곤 (경희대학교 동서의학대학원 의료공학전공) ;
  • 이항노 (경희대학교 동서의학대학원 의료공학전공) ;
  • 이정한 (건국대학교 의학공학부)
  • Published : 2003.05.01
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Abstract

In this paper, we introduce a magnetic noise shielding method to reduce the noise effects in permanent magnet based MRI systems. Through FEM electromagnetic analyses, we have shown that the magnetic noise component parallel to the main magnetic field is the major component that makes various artifacts in the images obtained with a permanent magnet based MRI. Based on the FEM analyses, we have developed an active magnetic noise shielding system composed of a magnetic field sensor, compensation coils, and a coil driving system. The shielding system has shown a noise rejection ratio of about 30dB at the frequency below several Hz. We have experimentally verified that the shielding system greatly improves the image quality in a 0.3 Tesla MRI system.

본 논문에서는 영구자석 자기공명영상시스템에 나쁜 영향을 기치는 외부 자기 잡음을 효율적으로 차폐하는 기술을 서술하였다. 유한요소법 전자계 해석을 통하여 영구자석의 주자계 방향과 일치하는 자기 잡음 성분이 자기공명영상에 주로 영향을 미치는 것을 밝혔고, 이의 해석 결과를 기반으로 자기잡음센서, 보상코일, 그리고 코일구동기로 구성되는 능동형 자기 잡음 차폐시스템을 개발하였다. 개발된 자기 잡음 차폐시스템은 수 Hz 미만의 저주파 대역의 자기 잡음에 대하여 30dB 이상의 차폐율을 보였으며, 0.3Tesla 전신형 자기 공명영상시스템에 자기 잡음 차폐시스템을 적용하여 자기 잡음에 의한 영상 잡음이 크게 개선됨을 실험적으로 밝혔다.

Keywords

References

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