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公开(公告)号：US5134374A
公开(公告)日：1992-07-28
申请号：US555269
申请日：1990-07-18
IPC分类号： G01R33/383 , G01R33/3873 , H01F7/02
CPC分类号： G01R33/383 , G01R33/3873 , H01F7/0278
摘要： A magnetic field control apparatus for establishing a uniform field of flux for use in magnetic resonance imaging has 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 segmented 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具有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，包括一个或多个内部分段的同心环，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。
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公开(公告)号：US4943774A
公开(公告)日：1990-07-24
申请号：US360028
申请日：1989-06-01
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。
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3.发明授权
公开(公告)号：US5194810A
公开(公告)日：1993-03-16
申请号：US813981
申请日：1991-12-26
IPC分类号： G01R33/383 , G01R33/3873 , H01F7/02
CPC分类号： G01R33/383 , G01R33/3873 , H01F7/0278
摘要： An open access superconducting MRI magnet includes a ferromagnetic frame open on at least two sides and having upper and lower end plates and at least two support posts. A superconducting coil assembly is mounted to each end plate for generating a magnetic flux field in a patient receiving area located between the end plates. A magnetic flux field shaping means is associated with each end plate. The flux field shaping means includes rose shims, inner rings mounted within the rose shims, and removable segments mounted to the rose shims. Transition plates are located between the support ports and end plates for minimizing flux leakage. In addition the end plates are formed with a varying thickness such that a cross section taken perpendicular to a return path of magnetic flux is substantially constant.
摘要翻译： 开放式超导MRI磁体包括在至少两个侧面上开放的铁磁框架，并且具有上端板和下端板以及至少两个支撑柱。 超导线圈组件安装到每个端板，用于在位于端板之间的患者接收区域中产生磁通场。 磁通量场成形装置与每个端板相关联。 通量场成形装置包括玫瑰垫片，安装在玫瑰垫片内的内圈和安装在玫瑰垫片上的可拆卸部分。 过渡板位于支撑端口和端板之间，以最小化漏磁。 此外，端板形成为具有变化的厚度，使得垂直于磁通的返回路径取得的横截面基本上是恒定的。
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公开(公告)号：US5412363A
公开(公告)日：1995-05-02
申请号：US259914
申请日：1994-06-10
IPC分类号： H01F7/02 , A61B5/055 , F25B9/14 , F25D19/00 , G01R33/38 , G01R33/3815 , H01F6/00 , H01F6/04 , H01F7/22 , G01V3/00
CPC分类号： G01R33/3806 , G01R33/3815 , H01F6/00 , H01F6/04 , F25B9/14 , F25D19/006 , Y10S505/893
摘要： An open access MRI magnet includes a ferromagnetic frame open on at least two sides and having upper and lower end plates and at least two support columns. A superconducting coil assembly is mounted to each end plate for generating a magnetic flux field in a patient receiving area located between the end plates. Each superconducting coil assembly includes a toroidal vacuum tight vessel, insulation, and one or more temperature shields mounted within the vacuum tight vessel. One or more coils of superconducting wire is wound within the vacuum vessel, and is coupled to a power source and to a persistent switch for maintaining a constant flow of current with no power consumption. A return path for the flux is provided by the end plates and support posts of the frame. The superconducting coils, the thermal shields, and the persistent switch are cooled by a cryocooler, by means of conduction through solid thermal conductors or by a combination of conduction and convection, through a fluid cooling circuit, without the consumption of a liquid cryogen.
摘要翻译： 开放式磁共振磁体包括在至少两个侧面上开放并具有上端板和下端板以及至少两个支撑柱的铁磁框架。 超导线圈组件安装到每个端板，用于在位于端板之间的患者接收区域中产生磁通场。 每个超导线圈组件包括环形真空密封容器，绝缘体和安装在真空密封容器内的一个或多个温度屏蔽件。 超导线的一个或多个线圈缠绕在真空容器内，并且耦合到电源和持久开关，用于在没有功率消耗的情况下保持恒定的电流流动。 用于焊剂的返回路径由框架的端板和支撑柱提供。 超导线圈，热屏蔽和持续开关由低温冷却器通过固体热导体传导或通过传导和对流的组合通过流体冷却回路冷却而不消耗液体冷冻剂。
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公开(公告)号：US5003276A
公开(公告)日：1991-03-26
申请号：US392609
申请日：1989-08-11
IPC分类号： G01R33/383 , G01R33/3873
CPC分类号： G01R33/383 , G01R33/3873
摘要： Ferromagnetic pieces are mounted on a plurality of nonmagnetic radial rods located at desired locations parallel to a pole face of a permanent magnet used in a magnetic resonance imaging apparatus. The pieces comprise plates which are translatable radially along each rod. Each rod carrying the plates are each rotatable about the rod axis to produce an error field cancelling environmentally induced, low order perturbations. A method for accomplishing same is also included. In a preferred embodiment, the plates are mounted on radial rods positioned at equal angles from one another, preferably thirty degrees (30.degree.) apart and arranged as spokes of a wheel.
摘要翻译： 铁磁片安装在位于平行于磁共振成像设备中使用的永磁体的极面的期望位置处的多个非磁性径向杆上。 这些件包括可沿着每个杆径向平移的板。 承载板的每个杆各自可以围绕杆轴线旋转以产生消除环境诱导的低阶扰动的误差场。 还包括实现其的方法。 在一个优选实施例中，板被安装在径向杆上，径向杆彼此相等地设置，优选地相差30度（30度）并且被布置为轮的轮辐。
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6.发明授权Open access superconducting MRI magnet having an apparatus for reducing magnetic hysteresis in superconducting MRI systems 失效具有用于降低超导MRI系统中磁滞的设备的开放式超导MRI磁体
公开(公告)号：US5414399A
公开(公告)日：1995-05-09
申请号：US812080
申请日：1991-12-19
IPC分类号： G01R33/385 , G01R33/3873 , H01F7/20 , G01R33/28
CPC分类号： G01R33/3806 , G01R33/385 , G01R33/3873
摘要： A MRI superconducting magnet having an open access frame with spaced parallel end plates, a superconducting coil assembly associated with each end plate, and gradient coils associated with each end plate includes an apparatus for minimizing hysteresis. The apparatus for minimizing hysteresis comprises a layer of nonferromagnetic conducting material interposed between the gradient coils and end plates. The interposed layer carries eddy currents induced by time varying magnetic fields produced by the gradient coils, thereby minimizing AC eddy current hysteresis from the end plates. The layer preferably has a thickness of at least one skin depth at the frequency associated with the time varying magnetic field. In another embodiment, each end plate has a plurality of slits formed therein for eliminating eddy currents in the end plates.
摘要翻译： MRI超导磁体具有带有间隔开的平行端板的开放式进入框架，与每个端板相关联的超导线圈组件以及与每个端板相关联的梯度线圈包括用于最小化滞后的装置。 用于最小化滞后的装置包括介于梯度线圈和端板之间的非铁磁导电材料层。 插入的层承载由梯度线圈产生的时变磁场引起的涡流，从而最小化来自端板的交流涡流滞后。 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。 在另一个实施例中，每个端板具有形成在其中的多个狭缝，用于消除端板中的涡流。
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7.发明授权Magnetic resonance imaging magnet having minimally symmetric ferromagnetic shield 失效具有最小对称铁磁屏蔽的磁共振成像磁体
公开(公告)号：US4931759A
公开(公告)日：1990-06-05
申请号：US334291
申请日：1989-04-06
IPC分类号： G01R33/387 , A61B5/055 , G01R33/3815 , G01R33/3873 , G01R33/421
CPC分类号： G01R33/421 , G01R33/3815 , G01R33/3873
摘要： A magnetic resonance imaging magnet has a solenoidal superconducting winding producing a magnetic field and defining an examination region within a bore thereof. The examination region receives a body to be examined. The solenoidal superconducting winding generates a quasi-static magnetic field for aligning atomic nuclei in the body being examined. A two-fold or minimally symmetric ferromagnetic shield has a pair of magnetic flux return paths positioned on opposite sides of the solenoidal superconducting winding for reducing the magnetic field intensity in a region proximate to and outside of the solenoidal superconducting winding. A magnetic field inhomogeneity compensating system reduces magnetic field inhomogeneities introduced into the magnetic field within the examination region by the minimally symmetric ferromagnetic shield to provide a highly uniform quasi-static magnetic field within the examination region.
摘要翻译： 磁共振成像磁体具有产生磁场的螺线管超导绕组并且在其孔内限定检查区域。 检查区域接受检查的身体。 螺线管超导绕组产生准静态磁场，用于对准被检体内的原子核。 双重或最小对称的铁磁屏蔽具有位于螺线管超导绕组的相对侧上的一对磁通返回路径，用于减小靠近和超出螺线管超导绕组的区域内的磁场强度。 磁场不均匀性补偿系统通过最小对称的铁磁屏蔽减小引入到检查区域内的磁场的磁场不均匀性，以在检查区域内提供高度均匀的准静态磁场。
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公开(公告)号：US06438966B1
公开(公告)日：2002-08-27
申请号：US09881642
申请日：2001-06-13
IPC分类号： F25B900
CPC分类号： F25D19/006 , F25B9/10 , H01F6/04
摘要： A sleeve assembly for thermally interconnecting a pulse tube, two stage cryocooler with a superconducting device includes a heat transfer cylinder, a heat transfer receptacle and a wall extending therebetween to define a passageway. The heat transfer receptacle is formed with a tapered recess wherein a tapered cooling probe of the cryocooler is urged against the heat transfer receptacle to establish thermal communication therebetween. A cooling element of the cryocooler is disposed in the heat transfer cylinder to establish thermal communication therebetween. In operation, the cryocooler moves relative to the sleeve assembly between a first configuration wherein the cryocooler is engaged with the sleeve assembly to establish thermal communication therebetween and a second configuration wherein the cryocooler is disengaged with the sleeve assembly. An expandable bellows which interconnects the cryocooler with the sleeve assembly will maintain thermal insulation therebetween when the cryocooler is disengaged from the sleeve assembly.
摘要翻译： 用于将脉冲管，两级制冷器与超导装置热互连的套筒组件包括传热圆筒，传热容器和在其间延伸以限定通道的壁。 传热容器形成有锥形凹槽，其中低温冷却器的锥形冷却探针被推靠在传热容器上以在它们之间建立热连通。 低温冷却器的冷却元件设置在传热圆筒中，以在它们之间建立热连通。 在操作中，低温冷却器相对于套筒组件在第一配置之间移动，其中低温冷却器与套筒组件接合以在其间建立热连通，而第二配置，其中低温冷却器与套筒组件分离。 将低温冷却器与套管组件相互连接的可膨胀波纹管在低温冷却器与套筒组件脱离接合时将保持其间的热绝缘。
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公开(公告)号：US4841268A
公开(公告)日：1989-06-20
申请号：US101517
申请日：1987-09-28
CPC分类号： H01F6/065 , G01R33/3815 , G01R33/3804
摘要： A magnet system, having permanently installed power leads, for providing a magnetic field. The system includes a vacuum vessel and a cryogenic containment vessel supported within the vacuum vessel. The containment vessel holds a main coil formed of superconductive wire, along with a quantity of liquid helium to maintain the wire below its critical temperature. The power leads, which supply energy to the coil from a power supply outside the vacuum vessel, also take energy from the coil to a load resistor outside the vacuum vessel when the coil is discharged, each include an elongate metallic tube. The magnet system also includes a solenoid controlled valve which is responsive to the passage of electric current through the tubes of the power leads to cause helium gas resulting from the boiling of liquid helium in the containment vessel to be vented to atmosphere through the tube thereby cooling them.
摘要翻译： 磁体系统，永久地安装电源线，用于提供磁场。 该系统包括真空容器和支撑在真空容器内的低温容纳容器。 安全壳容纳由超导线形成的主线圈以及一定量的液氦，以将线保持在其临界温度以下。 从真空容器外部的电源向线圈供给能量的电源线，当线圈被排出时，也将能量从线圈吸收到真空容器外部的负载电阻上，每个电源都包括细长的金属管。 磁体系统还包括电磁控制阀，其响应于通过电力引线的管的电流的通过，导致由安全壳中的液氦沸腾产生的氦气通过管排出到大气中，从而冷却 他们。
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公开(公告)号：US4782671A
公开(公告)日：1988-11-08
申请号：US101516
申请日：1987-09-28
IPC分类号： A61B10/00 , A61B5/055 , F17C3/08 , F25J1/00 , G01R33/20 , G01R33/38 , G01R33/3815 , H01F7/20 , H01L39/00 , H05K9/00 , F25B19/00
CPC分类号： F25J1/0276 , F17C3/085 , G01R33/3815 , F17C2201/0119 , F17C2203/0312 , F17C2203/032 , F17C2203/0391 , F17C2221/014 , F17C2221/017 , F17C2223/0161 , F17C2223/033 , F17C2227/0341 , F17C2265/034 , F17C2270/0509 , F17C2270/0536 , F25J2290/42
摘要： An improvement in cooling apparatus in a magnet system for providing a localized, substantially homogeneous magnetic field for use in magnetic resonance imaging. The magnet system includes a vacuum vessel, a cryogenic containment vessel inside the vacuum vessel and having a coil of superconductive wire along with a quantity of liquid helium to maintain the wire below its critical temperature. The system also includes an inner thermal radiation shield between the containment vessel and the vacuum vessel and an outer thermal radiation shield between the inner shield and the vacuum vessel. A cryogenic refrigerator is supported by the vacuum vessel and extends inside. This refrigerator has a first-stage heat station cooling the outer shield and second-stage heat station for cooling the inner shield. The improvement includes the provision of a tank holding a quantity of liquid nitrogen. This tank is supported in good heat transfer relationship with the first-stage heat station between the vacuum vessel and the outer shield and is spaced from the outer shield. Tubing is provided for transferring the liquid nitrogen from the tank so that it boils in good heat transfer relationship with the outer shield and also returns gas resulting from the boiling of the liquid nitrogen back to the tank where the refrigerator condenses it in the tank. A method of using the cooling apparatus in the event the refrigerator is not functional, is also disclosed.
摘要翻译： 用于提供用于磁共振成像的局部的，基本均匀的磁场的磁体系统中的冷却装置的改进。 磁体系统包括真空容器，真空容器内部的低温容纳容器，并且具有一束超导线以及一定量的液氦，以将电线保持在其临界温度以下。 该系统还包括在容纳容器和真空容器之间的内部热辐射屏蔽以及内部屏蔽和真空容器之间的外部热辐射屏蔽。 低温冰箱由真空容器支撑并在内部延伸。 该冰箱具有冷却外屏蔽的第一级加热站和用于冷却内屏蔽的第二级加热站。 改进之处在于提供容纳液氮的罐。 该罐与真空容器和外罩之间的第一级加热站具有良好的传热关系，并与外护罩间隔开。 提供管道用于从罐转移液氮，使得其与外部屏蔽件具有良好的热传递关系，并且将从液氮的沸腾产生的气体返回到罐中，其中冰箱将其冷凝在罐中。 还公开了在冰箱不起作用的情况下使用冷却装置的方法。
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