-
公开(公告)号：US5396208A
公开(公告)日：1995-03-07
申请号：US957469
申请日：1992-10-06
IPC分类号： A61B5/055 , G01R33/20 , G01R33/38 , G01R33/381 , G01R33/3815 , G01R33/3873 , G01V3/00
CPC分类号： G01R33/3873 , G01R33/3815 , G01R33/3806
摘要： An extremely efficient magnet system having a comparatively large angle of aperture can be obtained for magnetic resonance imaging by a reduction of fields of all orders in a common approach affecting active and passive as well as positive and negative oriented coil elements. Passive soft-magnetic ring segments are arranged in two pairs and located within a plurality of larger diameter active magnetic coils. The active coils include a central coil and outer coils wherein the outer coils are smaller than the central coil. The coils are in a helium Dewar vessel and arranged such that the system has an aperture of about 90.degree.. The central active coil may have a larger radius than the smaller outer coils.
摘要翻译： 通过影响有源和无源以及正和负取向线圈元件的共同方法，可以通过减少所有阶数的场来获得具有相对较大的孔径角度的非常有效的磁体系统。 无源软磁环段被布置成两对并且位于多个较大直径的有源磁性线圈内。 有源线圈包括中心线圈和外线圈，其中外线圈小于中心线圈。 线圈在氦杜瓦容器中并且布置成使得系统具有约90°的孔径。 中心有源线圈可以具有比较小的外部线圈更大的半径。
-
2.发明授权
公开(公告)号：US5235282A
公开(公告)日：1993-08-10
申请号：US800200
申请日：1991-11-27
IPC分类号： A61B5/055 , G01R33/20 , G01R33/421 , H01F7/20
CPC分类号： G01R33/421
摘要： In a magnetic resonance apparatus comprising a superconducting magnet system (1) for generating a steady magnetic field there is also included a superconducting shielding coil system (22) in order to compensate for magnetic field variations induced in the magnet by external magnetic flux variations. The shielding coil system (22) comprises coil sections (24) of different diameters.
-
公开(公告)号：US4878024A
公开(公告)日：1989-10-31
申请号：US233307
申请日：1988-08-17
CPC分类号： G01R33/3854
摘要： In a gradient coil system for a magnetic resonance apparatus arc conductors of notably X coils and Y coils are stacked axially or radially so as to form rigid stacks. The arc conductors are interconnected by means of electrical conductors and the stacks are also interconnected, so that a rigid, self-supporting coil system is obtained. Because the coil system is composed of rigid elements, is comparatively open and does not require a coil former, the production of noise in a magnetic resonance apparatus comprising such a coil system is substantially reduced and field disturbances due to coil deformations are also reduced.
-
公开(公告)号：US5245306A
公开(公告)日：1993-09-14
申请号：US957537
申请日：1992-10-05
申请人： Johannes A. Overweg
发明人： Johannes A. Overweg
IPC分类号： A61B5/055 , G01R33/38 , G01R33/381 , G01R33/3875 , G01R33/421
CPC分类号： G01R33/3875 , G01R33/421
摘要： A magnet system for generating a uniform magnetic field in an examination zone (5) in an accommodation space of magnetic resonance apparatus is formed by a first, approximately cylindrical electromagnetic coil system (1) which encloses the examination zone and which is symmetrically arranged relative to a symmetry axis (9) and relative to a asymmetry plane (11) extending perpendicularly to the symmetry axis, and a second, approximately cylindrical electromagnetic coil system (7) which is arranged so as to be symmetrical relative to the symmetry axis and relative to the symmetry plane and which is arranged so as to be concentric with the first coil system, the magnetic dipole moments of the first and the second coil system being oppositely directed and substantially equal. The first coil system (1) includes a central coil (13) which is symmetrically arranged relative to the symmetry plane (11) and two pairs of further coils (15, 17) which are symmetrically arranged relative to the symmetry plane, the second coil system (7) including a central coil (21) symmetrically arranged relative to the symmetry plane and a pair of further coils (23) symmetrically arranged relative to the symmetry plane. As a result, despite the use of only eight coils the magnet system generates a highly uniform central magnetic field and only a very small stray field.
-
公开(公告)号：US4845432A
公开(公告)日：1989-07-04
申请号：US127826
申请日：1987-12-01
申请人： Johannes A. Overweg
发明人： Johannes A. Overweg
IPC分类号： G01R33/20 , A61B5/055 , G01R33/38 , G01R33/385
CPC分类号： G01R33/385
摘要： A magnetic resonance imaging apparatus utilizes a gradient coil system with different arc angles for different arc conductors of the essentially saddle-shaped coil elements of the magnet. As result, the arc conductors can be oriented nearer to the radial symmetry plane so that not only the spatial field homogeneity in an active zone is maintained or improved, but also the efficiency of the gradient magnet system is substantially increased and the power stored in the coil is reduced, thus enabling faster switching.
-
公开(公告)号：US06466812B1
公开(公告)日：2002-10-15
申请号：US09517715
申请日：2000-03-02
IPC分类号： A61B5055
CPC分类号： G01R33/381 , G01R33/62
摘要： The invention relates to an MR method in which the nuclear magnetization is enhanced under the influence of a first steady magnetic field and a second steady magnetic field acts on the nuclei previously influenced by the first magnetic field. According to the invention, the two magnetic fields overlap in time and enclose an angle other than 0° relative to one another, the angle preferably amounting to 90°. The enhanced nuclear magnetization is then sustained after the activation of the first steady magnetic field while the direction of the nuclear magnetization is determined by the second steady magnetic field. The use of two mutually perpendicular magnetic fields is advantageous notably for Overhauser imaging methods, because it enables the use of mutually perpendicular RF fields for the ESR saturation and the MR excitation, thus uncoupling the coils generating such RF fields from one another.
摘要翻译： 本发明涉及一种MR方法，其中核磁化在第一稳定磁场的影响下增强，第二稳定磁场作用在先前受第一磁场影响的核上。 根据本发明，两个磁场在时间上重叠并且相对于彼此包围0°以外的角度，该角度优选为90°。 然后在第一稳定磁场激活之后维持增强的核磁化，而核磁化的方向由第二稳定磁场确定。 两个相互垂直的磁场的使用特别适用于Overhauser成像方法，因为它能够使用相互垂直的RF场用于ESR饱和和MR激励，从而使产生这种RF场的线圈彼此分离。
-
公开(公告)号：US5426366A
公开(公告)日：1995-06-20
申请号：US161949
申请日：1993-12-02
IPC分类号： G01R33/3815 , G01R33/421 , H01F6/00 , G01R33/20
CPC分类号： G01R33/3815 , G01R33/421 , H01F6/006
摘要： The apparatus comprises a magnet system which is rotationally symmetrically arranged about a central axis (9) and which comprises a superconducting inner coil system (1) for generating a steady magnetic field in a measurement space (5) within the magnet system, and also comprises an outer coil system (7) which is arranged so as to be coaxial with the inner coil system and which is electrically connected in series therewith in order to shield the environment from the magnetic field generated by the inner coil system. The magnet system can be bridged by of a superconducting persistent current switch (33) and comprises a superconducting shunt (37) which bridges a pan of the magnet system which is situated between first and second connection points (39, 41). In order to improve the shielding of the measurement space (5) from the effects of external magnetic fields, at least one turn of a coil (17) forming part of the magnet system is situated between at least one of the connection points (39, 41) and the nearest end of the inner coil system (1 ). The shielding effect can be further enhanced by utilizing more than one shunt (37, 53).
摘要翻译： 该装置包括围绕中心轴线（9）旋转对称布置的磁体系统，该磁体系统包括用于在磁体系统内的测量空间（5）中产生稳定磁场的超导内部线圈系统（1），并且还包括 外部线圈系统（7）被布置成与内部线圈系统同轴并与其串联电连接，以便将环境与由内部线圈系统产生的磁场隔离。 磁体系统可以由超导持续电流开关（33）桥接，并且包括桥接位于第一和第二连接点（39,41）之间的磁体系统盘的超导分流器（37）。 为了改善测量空间（5）的屏蔽与外部磁场的影响，构成磁体系统的一部分的线圈（17）的至少一圈位于至少一个连接点（39， 41）和内线圈系统（1）的最近端。 通过利用多个分流器可以进一步提高屏蔽效果（37,53）。
-
公开(公告)号：US4931735A
公开(公告)日：1990-06-05
申请号：US347599
申请日：1989-05-02
申请人： Johannes A. Overweg , Paul B. Bunk
发明人： Johannes A. Overweg , Paul B. Bunk
IPC分类号： G01R33/381 , A61B5/055 , G01R33/38 , G01R33/421 , H01F7/20
CPC分类号： G01R33/421 , Y10S505/844
摘要： In a magnetic resonance apparatus a system of concentric cylinders of superconductive material maintain an effective steady magnetic field in a measured space within the inner cylinder which field is very homogeneous and is, moreover, very constant in time without requiring a large electric power. In a particular embodiment a magnetic field cylinder produces a strong magnetic field, a stabilization cylinder within the magnetic field cylinder ensures a good homogeneity and stabilization of the effective magnetic field, while a screening cylinder provided outside the magnetic field cylinder reduces the external stray field of the system.
-
9.发明授权
公开(公告)号：US4893083A
公开(公告)日：1990-01-09
申请号：US233308
申请日：1988-08-17
CPC分类号： G01R33/34046 , G01R33/385
摘要： In a magnetic resonance apparatus a gradient coil system and an r.f. coil are combined so as to form a magnetically, electrically and structurally integrated coil system with current conductors in substantially the same cylinder. Thus, a substantial saving is realized as regards the activation energy required for generating gradient fields as well as for generating r.f. fields and notably r.f. stray-fields are also reduced.
-
公开(公告)号：US5917395A
公开(公告)日：1999-06-29
申请号：US882868
申请日：1997-06-26
申请人： Johannes A. Overweg
发明人： Johannes A. Overweg
IPC分类号： G01R33/381 , A61B5/055 , G01R33/38 , G01R33/3815 , G01R33/3873 , H01F7/00
CPC分类号： G01R33/3806 , G01R33/3815 , G01R33/3873
摘要： A magnetic resonance device has a main field magnet system which generates a steady magnetic field in an examination zone. The main field magnet system includes a yoke structure which consists of two yoke plates and a yoke wall interconnecting the two yoke plates, a pole block which is arranged inside the yoke device, and below an examination zone, and a coil which is arranged within the yoke system and above the examination zone. In order to ensure that a patient present in the examination zone can also undergo further treatments and is freely accessible during an MR examination, the inner space of the coil as well as the space between the coil and the examination zone remains free from components of the magnet system, the coil being constructed so as to be ring-shaped and encloses the examination zone essentially in such a manner that the patient is freely accessible from above and from the sides.
摘要翻译： 磁共振装置具有主磁场系统，其在检查区中产生稳定的磁场。 主磁场系统包括轭结构，该轭结构由两个磁轭板和互连两个磁轭板的磁轭壁组成，一磁极组件布置在磁轭装置的内部并位于检查区的下方， 轭系统和检查区以上。 为了确保存在于检查区域的患者也可以进行进一步的治疗，并且在MR检查期间可以自由进入，线圈的内部空间以及线圈与检查区域之间的空间保持不含 磁体系统，线圈被构造成环形并且基本上以使得患者可以从上方和从侧面自由接近的方式包围检查区域。
-
-
-
-
-
-
-
-
-
搜索结果
12 条记录 (耗时 0.022 秒)
