Active-passive electromagnetic shielding to reduce MRI acoustic noise
    5.
    发明授权
    Active-passive electromagnetic shielding to reduce MRI acoustic noise 失效
    主动被动电磁屏蔽减少MRI声学噪声

    公开(公告)号:US07375526B2

    公开(公告)日:2008-05-20

    申请号:US11551413

    申请日:2006-10-20

    IPC分类号: G01V3/00

    CPC分类号: G01R33/3854 G01R33/4215

    摘要: The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively shielded gradient windings and passive shielding should be designed concurrently in order to substantially optimize the gradient linearity and reduce the eddy currents generated in metallic parts of the magnetic resonance imaging system.

    摘要翻译: 本发明提供了一种用于降低磁共振成像装置中的声学噪声的装置,其包括位于主动屏蔽的梯度绕组元件外部的无源屏蔽,以便减少在不需要的方向上扩展到梯度线圈组件外部的场的大小并与磁体相互作用 低温恒温器或其他金属磁体部件,引起导致声音噪声的涡流。 无源屏蔽元件是位于圆柱形磁体系统中的圆柱形梯度线圈组件的外半径上的导电层,位于梯形线圈组件的端部的导电层位于圆柱形磁体系统中,导电层位于主动屏蔽梯度内 在圆柱形磁体系中缠绕内部元件。 被动屏蔽也可以位于与磁体低温恒温器振动隔离的分离结构上。 主动屏蔽的梯度绕组还可以延伸到主动屏蔽的梯度绕组的端部的部分,并且还可以延伸到主动屏蔽的梯度绕组的内部的内半径内的部分。 主动屏蔽梯度绕组和无源屏蔽应同时设计,以便基本上优化梯度线性并减少在磁共振成像系统的金属部分中产生的涡流。

    Active-passive electromagnetic shielding to reduce MRI acoustic noise
    6.
    发明授权
    Active-passive electromagnetic shielding to reduce MRI acoustic noise 有权
    主动被动电磁屏蔽减少MRI声学噪声

    公开(公告)号:US07141974B2

    公开(公告)日:2006-11-28

    申请号:US10925691

    申请日:2004-08-25

    IPC分类号: G01V3/00

    CPC分类号: G01R33/3854 G01R33/4215

    摘要: The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively shielded gradient windings and passive shielding should be designed concurrently in order to substantially optimize the gradient linearity and reduce the eddy currents generated in metallic parts of the magnetic resonance imaging system.

    摘要翻译: 本发明提供了一种用于降低磁共振成像装置中的声学噪声的装置,其包括位于主动屏蔽梯度绕组元件外部的无源屏蔽,以便减小在不需要的方向上扩展到梯度线圈组件外部的场的幅度并与磁体相互作用 低温恒温器或其他金属磁体部件,引起导致声音噪声的涡流。 无源屏蔽元件是位于圆柱形磁体系统中的圆柱形梯度线圈组件的外半径上的导电层,位于梯形线圈组件的端部的导电层位于圆柱形磁体系统中,导电层位于主动屏蔽梯度内 在圆柱形磁体系中缠绕内部元件。 被动屏蔽也可以位于与磁体低温恒温器振动隔离的分离结构上。 主动屏蔽的梯度绕组还可以延伸到主动屏蔽的梯度绕组的端部的部分,并且还可以延伸到主动屏蔽的梯度绕组的内部的内半径内的部分。 主动屏蔽梯度绕组和无源屏蔽应同时设计,以便基本上优化梯度线性并减少在磁共振成像系统的金属部分中产生的涡流。

    ACTIVE-PASSIVE ELECTROMAGNETIC SHIELDING TO REDUCE MRI ACOUSTIC NOISE
    7.
    发明申请
    ACTIVE-PASSIVE ELECTROMAGNETIC SHIELDING TO REDUCE MRI ACOUSTIC NOISE 失效
    主动被动电磁屏蔽减少MRI声音噪声

    公开(公告)号:US20080094062A1

    公开(公告)日:2008-04-24

    申请号:US11551413

    申请日:2006-10-20

    IPC分类号: G01V3/00

    CPC分类号: G01R33/3854 G01R33/4215

    摘要: The present invention provides an apparatus for reducing acoustic noise in a magnetic resonance imaging device including passive shielding located outside the actively shielded gradient winding elements in order to reduce the magnitude of fields that spread outside the gradient coil assembly in unwanted directions and interact with the magnet cryostat or other metallic magnet parts, inducing eddy currents that cause consequent acoustic noise. The passive shielding elements are conducting layers located on the outer radius of the cylindrical gradient coil assembly in a cylindrical magnet system, conducting layers located at the ends of the gradient coil assembly in a cylindrical magnet system, and conducting layers located inside the actively shielded gradient winding inner elements in a cylindrical magnet system. The passive shielding could also be located on separate structures that are vibrationally isolated from the magnet cryostat. The actively shielded gradient winding can also be extended to portions at the ends of the actively shielded gradient winding and further to portions inside the inner radius of the inner portion of the actively shielded gradient winding. The actively shielded gradient windings and passive shielding should be designed concurrently in order to substantially optimize the gradient linearity and reduce the eddy currents generated in metallic parts of the magnetic resonance imaging system.

    摘要翻译: 本发明提供了一种用于降低磁共振成像装置中的声学噪声的装置,其包括位于主动屏蔽梯度绕组元件外部的无源屏蔽,以便减小在不需要的方向上扩展到梯度线圈组件外部的场的幅度并与磁体相互作用 低温恒温器或其他金属磁体部件,引起导致声音噪声的涡流。 无源屏蔽元件是位于圆柱形磁体系统中的圆柱形梯度线圈组件的外半径上的导电层,导电层位于梯形线圈组件的圆柱形磁体系统的端部,导电层位于主动屏蔽梯度内 在圆柱形磁体系中缠绕内部元件。 被动屏蔽也可以位于与磁体低温恒温器振动隔离的分离结构上。 主动屏蔽的梯度绕组还可以延伸到主动屏蔽的梯度绕组的端部的部分,并且还可以延伸到主动屏蔽的梯度绕组的内部的内半径内的部分。 主动屏蔽梯度绕组和无源屏蔽应同时设计,以便基本上优化梯度线性并减少在磁共振成像系统的金属部分中产生的涡流。