公开(公告)号：US4980641A

公开(公告)日：1990-12-25

申请号：US393400

申请日：1989-08-11

申请人： Bruce C. Breneman ,  Raymond E. Sarwinski ,  Yen-Hwa L. Hsu

发明人： Bruce C. Breneman ,  Raymond E. Sarwinski ,  Yen-Hwa L. Hsu

IPC分类号： G01R33/38 ,  G01R33/383 ,  G01R33/385 ,  G01R33/421

CPC分类号： G01R33/421 ,  G01R33/3806 ,  G01R33/383 ,  G01R33/385

摘要： An apparatus for minimizing hysteresis in a magnetic resonance imaging device of the type utilizing a pair of oppositely charged parallel pole faces forming a magnetic field therebetween, and gradient coils spaced apart from each pole face for producing time varying magnetic fields, comprises a layer of nonferromagnetic conducting material interposed between the pole face and the gradient coil. The interposed layer carries eddy currents induced by time varying magnetic fields produced by the gradient coils, thereby minimizing AC induced eddy current hysteresis from the pole faces. The layer preferably has a thickness of at least one skin depth at the frequency associated with the time varying magnetic field. The layer is preferably contiguous with the pole face, and comprises copper or aluminum. In another embodiment, each pole face has a plurality of slits therethrough radiating inward from the circumference for eliminating the eddy currents in the pole face. The slits in one pole face are preferably symmetrical to those in the other. There are preferably twenty-four (24) slits spaced fifteen degrees (15.degree.) apart. There is also disclosed the method for accomplishing the same.

摘要翻译： 一种用于最小化磁共振成像装置中的磁滞的装置，该磁共振成像装置利用在它们之间形成磁场的一对相反电荷的平行极面以及与每个极面间隔开的用于产生时变磁场的梯度线圈，包括非铁磁层 介于极面和梯度线圈之间的导电材料。 插入层承载由梯度线圈产生的由时变磁场引起的涡流，从而最小化从极面引起的AC感应涡流滞后。 该层优选地具有与时变磁场相关联的频率处的至少一个皮肤深度的厚度。 该层优选与极面相邻，并且包括铜或铝。 在另一个实施例中，每个极面具有从圆周向内辐射的多个狭缝，以消除极面中的涡流。 一个极面中的狭缝优选地与另一个极面对应。 优选分开间隔十五度（15°）的二十四（24）个狭缝。 还公开了实现该方法的方法。

公开(公告)号：US4943774A

公开(公告)日：1990-07-24

申请号：US360028

申请日：1989-06-01

申请人： Bruce C. Breneman ,  J. Wesley Parker ,  Raymond E. Sarwinski

发明人： Bruce C. Breneman ,  J. Wesley Parker ,  Raymond E. Sarwinski

IPC分类号： G01R33/383 ,  G01R33/3873 ,  H01F7/02

CPC分类号： H01F7/0278 ,  G01R33/383 ,  G01R33/3873

摘要： A magnetic field control apparatus for establishing a uniform field of flux for use in magnetic resonance imaging comprises a pair of opposed magnetic poles mounted on end plates of variable thickness. A pair of substantially flat parallel pole faces are attached to the facing surfaces of the magnetic poles. The end plates are supported by connecting members. In addition, there is included a plurality of segments movably mounted to the periphery of the pole face for adjusting the density of the magnetic field. The top and bottom end plates may have substantially identical concave portions on the opposite outside surfaces thereof. The magnetic poles and pole faces are preferably in the shape of thin, flat, circular plates. In one embodiment, there is included one or more inner concentric rings for further adjustably controlling the homogeneity of the uniform magnetic flux in the air gap between the opposing pole faces into which a patient can be inserted for magnetic resonance imaging. In another embodiment, the end plates are shaped so that the aggregate cross-sectional area taken in any plane perpendicular to the direction of the return flow of flux is substantially constant.

摘要翻译： 用于建立用于磁共振成像的通量的均匀磁场的磁场控制装置包括安装在可变厚度的端板上的一对相对的磁极。 一对基本上平坦的平行极面附接到磁极的相对表面。 端板由连接构件支撑。 此外，还包括可移动地安装到极面的周边的多个段，用于调节磁场的密度。 顶端板和底端板可以在其相对的外表面上具有基本上相同的凹部。 磁极和极面的形状优选为薄，平的圆形板。 在一个实施例中，包括一个或多个内同心环，用于进一步可调节地控制可插入患者以用于磁共振成像的相对极面之间的气隙中的均匀磁通的均匀性。 在另一个实施例中，端板被成形为使得在垂直于焊剂回流方向的任何平面中取得的骨截面面积基本上是恒定的。

公开(公告)号：US4743880A

公开(公告)日：1988-05-10

申请号：US101518

申请日：1987-09-28

申请人： Bruce C. Breneman ,  John R. Purcell ,  Sibley C. Burnett

发明人： Bruce C. Breneman ,  John R. Purcell ,  Sibley C. Burnett

IPC分类号： A61B10/00 ,  A61B5/055 ,  G01R33/20 ,  G01R33/3815 ,  G01R33/421 ,  H01F7/20 ,  H01F7/00

CPC分类号： G01R33/3815 ,  G01R33/421

摘要： A magnet system for providing a localized, substantially homogeneous field for use in medical magnetic resonance imaging and its incorporation into a method of siting. The magnet system includes a vacuum vessel defining a bore for receiving the subject of the imaging and having a first end and a second end. A cryogenic containment vessel is supported within the vacuum vessel and a single coil is disposed within the containment vessel for providing the magnetic field. The magnetic system also includes a shield assembly of ferromagnetic material positioned closely adjacent the outside of the vacuum vessel and including first and second end assemblies and a plurality of axially extending beam-like members interconnecting the end assemblies. The coil comprises a winding made up of thousands of turns of small superconductive wire and which is configured to compensate for the effect of the presence of the shield to provide the substantially homogeneous field at a predetermined location in the bore. The components of the shield assembly are adapted for mounting to said vacuum vessel after siting. This permits simplified siting of the magnet system in that the vacuum vessel with the components inside of it can be sited first and the components of the shield assembly thereafter mounted on the vacuum vessel. A method of manufacturing the magnet system is also disclosed.

公开(公告)号：US08729899B2

公开(公告)日：2014-05-20

申请号：US13178805

申请日：2011-07-08

申请人： Michael Steckner ,  Bruce C. Breneman

发明人： Michael Steckner ,  Bruce C. Breneman

IPC分类号： G01V3/00

CPC分类号： G01R33/421

摘要： A magnetic resonance imaging (MRI) system magnet includes at least one main electromagnet winding disposed within a first radius of the magnet and at least one bucking electromagnet winding disposed within a second radius, larger than the first radius of the magnet and configured to provide self-shielding magnetic fields that substantially reduce fringe magnetic fields outside the magnet produced by the main electromagnet winding. The combination of magnetic fields produced by both the main and bucking electromagnet windings inside the magnet conform to MRI requirements within at least an imaging volume. The main and bucking electro-magnet windings are configured so as to create a net fringe field outside the magnet within the range of 50-100 gauss at a distance within a range of 3-5 meters axially and 2-3 meters radially from a center of the magnet.

摘要翻译： 磁共振成像（MRI）系统磁体包括设置在磁体的第一半径内的至少一个主电磁体绕组和设置在第二半径内的至少一个屈曲电磁体绕组，其大于磁体的第一半径并且被配置为提供自身 所述磁场基本上减少由主电磁铁绕组产生的磁体外的边缘磁场。 磁体内部的主电磁铁和屈曲电磁铁绕组产生的磁场的组合符合至少一个成像体积内的MRI要求。 主电磁铁绕组被构造成在50-100高斯的范围内在磁体外部产生一个净边缘场，距离在3-5米的范围内，距中心径向2-3米 的磁铁。

公开(公告)号：US20130009642A1

公开(公告)日：2013-01-10

申请号：US13178805

申请日：2011-07-08

申请人： Michael Steckner ,  Bruce C. Breneman

发明人： Michael Steckner ,  Bruce C. Breneman

IPC分类号： G01R33/44

CPC分类号： G01R33/421

摘要： A magnetic resonance imaging (MRI) system magnet includes at least one main electromagnet winding disposed within a first radius of the magnet and at least one bucking electromagnet winding disposed within a second radius, larger than the first radius of the magnet and configured to provide self-shielding magnetic fields that substantially reduce fringe magnetic fields outside the magnet produced by the main electromagnet winding. The combination of magnetic fields produced by both the main and bucking electromagnet windings inside the magnet conform to MRI requirements within at least an imaging volume. The main and bucking electro-magnet windings are configured so as to create a net fringe field outside the magnet within the range of 50-100 gauss at a distance within a range of 3-5 meters axially and 2-3 meters radially from a center of the magnet.

摘要翻译： 磁共振成像（MRI）系统磁体包括设置在磁体的第一半径内的至少一个主电磁体绕组和设置在第二半径内的至少一个屈曲电磁体绕组，其大于磁体的第一半径并且被配置为提供自身 所述磁场基本上减少由主电磁铁绕组产生的磁体外的边缘磁场。 磁体内部的主电磁铁和屈曲电磁铁绕组产生的磁场的组合符合至少一个成像体积内的MRI要求。 主电磁铁绕组被构造成在50-100高斯的范围内在磁体外部产生一个净边缘场，距离在3-5米的范围内，距中心径向2-3米 的磁铁。

公开(公告)号：US5517121A

公开(公告)日：1996-05-14

申请号：US372345

申请日：1995-01-13

申请人： Leon Kaufman ,  Jianhua Li ,  Joseph W. Carlson ,  Bruce C. Breneman

发明人： Leon Kaufman ,  Jianhua Li ,  Joseph W. Carlson ,  Bruce C. Breneman

IPC分类号： G01R33/38 ,  G01V3/00

CPC分类号： G01R33/3806

摘要： Convenient side access to an image volume located within a two-pole, two-column main magnet of an MRI system is provided by rotating the symmetry axis of the magnet to be non-perpendicular with respect to the longitudinal axis of the patient transport and/or otherwise displacing the two column structures of the magnetic circuit so as to permit open and unobstructed access to the image volume along a direction perpendicular to the longitudinal axis of the patient transport.

摘要翻译： 通过使磁体的对称轴相对于患者输送的纵向轴线旋转而不对称地提供位于MRI系统的两极双列主磁体内的图像体积的便利侧进入和/ 或以其它方式移位磁路的两个列结构，以允许沿垂直于患者输送的纵向轴线的方向打开和畅通无阻地访问图像体积。

公开(公告)号：US5418462A

公开(公告)日：1995-05-23

申请号：US237256

申请日：1994-05-02

申请人： Bruce C. Breneman ,  Yen-Hwa Hsu ,  Jang-Yu Hsu

发明人： Bruce C. Breneman ,  Yen-Hwa Hsu ,  Jang-Yu Hsu

IPC分类号： A61B5/055 ,  G01R33/24 ,  G01R33/3873 ,  G01V3/00

CPC分类号： G01R33/3873 ,  G01R33/24

摘要： A method for using ferromagnetic shims to reduce the inhomogeneity of the magnetic field in a Diameter Spherical Volume (DSV) in the bore of a Magnetic Resonance Imaging (MRI) device is provided. More specifically, a magnetic field is established within the bore of the MRI device. An operator defines the DSV. The strength of the magnetic field is measured at the surface of the DSV. A Legendre polynomial is derived to model the inhomogeneity in the magnetic field in the DSV. A set of coefficients for the harmonic terms of the polynomial is calculated from the field strength measurements and segregated into three separate groups for evaluation. Each group of terms expresses field inhomogeneity in a unique set of spatial dimensions. Ferromagnetic shims are attached to the surface of the bore in individual dipole, linear bar, and ring arrangements to separately reduce the first, second, and third groups of harmonic coefficients to acceptable levels corresponding to a predetermined peak-to-peak inhomogeneity range.

摘要翻译： 提供了一种使用铁磁垫片来减少磁共振成像（MRI）装置的孔中的直径球体积（DSV）中的磁场的不均匀性的方法。 更具体地，在MRI装置的孔内建立磁场。 操作员定义DSV。 在DSV的表面测量磁场的强度。 导出勒让德多项式来模拟DSV中磁场的不均匀性。 从场强测量中计算出多项式谐波项的一组系数，并将其分离为三个独立的组进行评估。 每一组术语在一组独特的空间维度中表现出场不均匀性。 铁磁垫片以单独的偶极子，线性杆和环形布置附接到孔的表面，以将第一，第二和第三组谐波系数分别地减小到对应于预定的峰 - 峰不均匀性范围的可接受的水平。

公开(公告)号：US4768008A

公开(公告)日：1988-08-30

申请号：US80020

申请日：1987-07-31

申请人： John R. Purcell ,  Bruce C. Breneman ,  Sibley C. Burnett

发明人： John R. Purcell ,  Bruce C. Breneman ,  Sibley C. Burnett

IPC分类号： A61B10/00 ,  A61B5/055 ,  G01R33/381 ,  G01R33/3815 ,  H01F7/20 ,  H01F7/22

CPC分类号： G01R33/3815

摘要： A magnet system for use in magnetic resonance imaging. The system includes a vacuum vessel having a first wall assembly defining a bore for receiving the subject of the imaging and a pair of spaced metallic end plates welded to the ends of the first wall assembly. The system further includes a cryogenic containment vessel supported within the vacuum vessel and a coil disposed within the containment vessel for providing the magnetic field. The first wall assembly includes a weldable metallic cylindrical shell positioned intermediate the end plates and having a thickness insufficient without reinforcement to provide structural integrity during operation of the vacuum vessel. This first wall assembly further includes a reinforcement layer of a non-metallic material disposed about the metallic shell so that signals provided by gradient coils disposed inside the bore can more quickly penetrate the first wall assembly than if the metallic shell had sufficient thickness, without reinforcement to provide the necessary structural integrity.