音響遮蔽磁気コイル装置、磁気共鳴画像装置及びその作動方法

Japanese Patent JP3748883

B2

PCT No. PCT/GB94/01187 Sec. 371 Date Dec. 1, 1995 Sec. 102(e) Date Dec. 1, 1995 PCT Filed Jun. 1, 1994 PCT Pub. No. WO94/28430 PCT Pub. Date Dec. 8, 1994The invention describes apparatus for, and a method of, active acoustic screening and combined active acoustic and magnetic screening, of magnetic field coils, which pass a time varying current and which reside in relatively high static magnetic fields, typically greater than about 0.1 T. The invention is particularly well suited for acoustic screening of magnetic field gradient coils used in Magnetic Resonance Imaging (MRI). In a preferred embodiment a closed loop carrying current is arranged such that two different parts of the loop are mechanically coupled, dimensioned and arranged with respect to one another such that Lorentz forces experienced by the magnetic equipment are substantially reduced and preferably cancelled. In a different embodiment the invention is modified so as to permit simultaneous magnetic and acoustic screening. The invention overcomes existing problems of non-acoustically screened coils used in conjunction with high magnetic fields, by by reducing vibrational forces by cancelling them, within the gradient coil structure, rather than damping or absorbing emitted high levels of acoustic noise.

Peter Mansfield
Chapman, Barry Leonard Walter
Grover, Paul Martin
Bowter, Richard William

JP50042395A

February 22, 2006

June 01, 1994

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BTG International Limited

A61B5/055; G01R33/385; G01R33/421; H01F7/20

JP5091983A
JP3133428A
JP63292607A

Kazuo Shamoto
Shosuke Imai
Tadashi Masui
Tadahiko Kurita
Yasushi Kobayashi
Yoshio Akimoto

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