Polarizing Field Magnet Patents (Class 324/319)
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Publication number: 20100013473Abstract: A magnet arrangement includes (a) a first and a second head ring magnet each having a substantially circular geometry with respect to a centre axis and (b) a central ring magnet having a substantially circular geometry with respect to a centre axis. The central ring magnet is disposed between the first and second head ring magnet in direction of the centre axis. At least one of the magnets includes a first number of first magnets having at least one trapezoidal cross section and a second number of second magnets having at least one rectangular cross section. The second magnets are disposed in between the first magnets in circumferential direction. With this geometrical arrangement, magnets having a trapezoidal cross section include a guidance for a magnet having a rectangular cross section allowing the movements in radial direction of these last magnets.Type: ApplicationFiled: July 6, 2009Publication date: January 21, 2010Applicant: RWTH AACHENInventors: Bernhard BLUMICH, Ernesto Pablo DANIELI, Federico CASANOVA, Juan Francisco PERLO
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Patent number: 7639013Abstract: With a view toward implementing a thermal controlling method for making reversible a temperature characteristic of a magnetic field generator using permanent magnets small in Hcj, a magnetic field generator whose temperature characteristic is reversible, using permanent magnets small in Hcj, and an MRI apparatus provided with such a magnetic field generator, there is provided a method for controlling the temperature of a magnetic field generator having a pair of disc-shaped permanent magnets whose magnetic poles opposite in polarity to each other are opposed to each other with spacing defined therebetween, and a yoke that forms return passes for magnetic fluxes of the permanent magnets, comprising the steps of raising the temperature from room temperature to a temperature higher than the room temperature, maintaining the temperature higher than the room temperature, and lowering the temperature from the temperature higher than the room temperature to the room temperature, whereby the temperature characteristiType: GrantFiled: July 13, 2007Date of Patent: December 29, 2009Assignee: GE Medical Systems Global Technology Company, LLCInventors: Fengshun Tan, Weijun Shen, Yihe Hua, Liang Liu
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Patent number: 7626477Abstract: A cold mass for a superconducting magnet system in one example comprises a superconducting magnet, a cryogenic cooling circuit, and a magnet and cooling circuit support. The magnet and cooling circuit support comprises a substantially conductive coupler that serves to couple the superconducting magnet and the cryogenic cooling circuit. The cryogenic cooling circuit comprises an inlet path and a substantially upward outlet path. The inlet path avoids direct conductive thermal engagement with the substantially conductive coupler. The substantially upward outlet path comprises direct conductive thermal engagement with the substantially conductive coupler.Type: GrantFiled: November 28, 2005Date of Patent: December 1, 2009Assignee: General Electric CompanyInventors: Xianrui Huang, Paul Shadforth Thompson, Evangelos Trifon Laskaris
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Patent number: 7615998Abstract: A method and apparatus for actively controlling quench protection of a superconducting magnet includes a magnetic resonance imaging (MRI) system and a computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to detect a quench condition of the superconducting magnet. The instructions also cause the computer to actively control a quench protection system of the superconducting magnet in response to the detected quench condition.Type: GrantFiled: January 9, 2007Date of Patent: November 10, 2009Assignee: General Electric CompanyInventors: Xianrui Huang, Minfeng Xu
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Patent number: 7609062Abstract: Magnetic resonance device comprises a patient support table and a main field magnet. The main field magnet is supported so that it can be rotated around at least one axis. The patient support table is able to be rotated around an axis essentially perpendicular in respect of its table surface.Type: GrantFiled: December 20, 2006Date of Patent: October 27, 2009Assignee: Siemens AktiengesellschaftInventor: Jörg Roland
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Patent number: 7605589Abstract: A method for homogenizing a static magnetic field with a magnetic field distribution B0(r) for nuclear magnetic resonance spectroscopy by adjusting the currents Ci through the shim coils, thus creating spatial field distributions Ci·Si(r), where r stands for one, two, or three of the spatial dimensions x, y, and z, and said magnetic field distribution B0(r) has only a field component along z, in a working volume of a magnetic resonance apparatus with one or more radio frequency (=RF) coils (5) for inducing RF pulses and receiving RF signals within a working volume, said RF coils having a spatial sensitivity distribution of magnitudes B1k(r), and with shim coils (6) for homogenizing the magnetic field within the working volume, said shim coils (6) being characterized by their magnetic field distributions per unit current Si(r) and having components only along z, includes the following steps: (a) Mapping the magnetic field distribution B0(r) of the main magnetic field, (b) calculating a simulated spectrum ISType: GrantFiled: October 18, 2007Date of Patent: October 20, 2009Assignee: Bruker BioSpin AGInventors: Markus Weiger, Michael Fey, Thomas Speck
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Publication number: 20090237080Abstract: A magnetic field generator includes a magnetic circuit of an open magnetic path in which a uniform magnetic field can be generated with a simpler structure. A nuclear magnetic resonance device equipped with this magnetic filed generator is also provided. The magnetic field generator of an open magnetic path type includes: a first permanent magnet and a second permanent magnet which are arranged sequentially in a reference direction with a predetermined distance therebetween while directing the direction of magnetization in the reference direction, and a third permanent magnet and a fourth permanent magnet which are arranged sequentially between the first permanent magnet and the second permanent magnet along the reference direction while being in contact with each other or being spaced apart from each other with a predetermined distance therebetween.Type: ApplicationFiled: July 31, 2007Publication date: September 24, 2009Applicants: NATIONAL UNIVERSITY CORPORATION OKAYAMA UNIVERSITY, HITACHI METALS, LTD.Inventors: Hirokazu Kato, Norio Takahashi, Junichi Asaumi, Masaaki Aoki
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Patent number: 7592812Abstract: A magnetic resonance imaging apparatus includes: a static magnetic field generating unit which generates a static magnetic field, a measuring unit which measures the strength distribution characteristic of the static magnetic field, a determination unit which determines correction amounts for first- to nth-order (n is a natural number of more than one) components of the strength distribution characteristic of the static magnetic field by fixing the correction amount for at least one specific component which are part of the first- to nth-order components at a predetermined amount and determining the correction amounts for other components than the specific component on the basis of the strength distribution characteristic, and a correction magnetic field generating unit which generates correction magnetic fields to correct the static magnetic field on the basis of the correction amounts.Type: GrantFiled: March 30, 2007Date of Patent: September 22, 2009Assignees: Kabushiki Kaisha Toshiba, Toshiba Medical Systems CorporationInventor: Masato Ikedo
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Publication number: 20090212775Abstract: An apparatus for use in a magnetic resonance (MR) system, which generates an external MR magnetic field, is provided. A rotor comprises a rotor shaft with an axis along a length of the rotor shaft and a plurality of coils on the rotor shaft. A housing supports and surrounds the rotor, where a part of the housing surrounds sides of the rotor and where the part of the housing surrounding sides of the rotor is magnet free. A mount allows for the mounting of the housing to the MR system in a location where the MR system provides a magnetic field, wherein a component of the MR magnetic field that is perpendicular to the axis of the rotor shaft is at least 100 Gauss. An active timer applies a voltage to the plurality of coils with alternating polarity. Contacts provide an electrical connection between the active timer and the plurality of coils.Type: ApplicationFiled: February 27, 2008Publication date: August 27, 2009Applicant: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Prasheel Lillaney, Rebecca Fahrig, Arundhuti Ganguly, Norbert J. Pelc
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Patent number: 7579837Abstract: The invention concerns an arrangement for magnetic field measurement of a measurement object (in particular a gradient coil in a magnetic resonance apparatus) with a magnetic field sensor that is designed to measure a magnetic field of the measurement object and with a measurement mechanism on which the magnetic field sensor is arranged at a first position. The measurement object has detectable reference points that can be used for calibration of a spatial position of a position sensor. The calibrated position sensor is arranged at a second position of the measurement mechanism, such that, with the first position and the second position, a spatial position relative to the measurement object can be associated with each magnetic field strength that is measured by the magnetic field sensor.Type: GrantFiled: May 29, 2008Date of Patent: August 25, 2009Assignee: Siemens AktiengesellschaftInventors: Sascha Fath, Alexander Granzer
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Patent number: 7579838Abstract: Systems, methods and apparatus are provided through which a partially elongated field-of-view in a magnetic resonance imaging system is generated either by an asymmetric primary coil or a conventional symmetrical primary coil with a supplementary high odd-order shim that elongates the field-of-view towards one end of the bore. For significantly increased efficiency, the high odd-order shim can evoke specific parts of the primary coil by injecting additional current and/or subtracting current from specific turns, as required.Type: GrantFiled: November 18, 2005Date of Patent: August 25, 2009Assignee: General Electric CompanyInventor: Timothy James Hollis
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Patent number: 7567082Abstract: A magnetic resonance imaging apparatus includes a gantry with a gradient coil which applies a gradient magnetic field to a subject in a static magnetic field, a bed which slides a top board in a longitudinal direction of the top board with the subject placed thereon, a high-frequency coil which applies the gradient magnetic field and a high-frequency pulse signal to the subject, and detects a magnetic resonance signal emitted from the subject, and a damping member which damps noise which occurs when the gradient coil is driven, or a support member which supports the gradient coil, the damping member or the support member providing an asymmetrical structure with respect to a plane perpendicular to the longitudinal direction.Type: GrantFiled: January 17, 2007Date of Patent: July 28, 2009Assignees: Kabushiki Kaisha Toshiba, Toshiba Medical Systems CorporationInventor: Hiromitsu Takamori
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Patent number: 7567158Abstract: A magnet arrangement (M, M?, M?, M??) for generating a magnetic field in the direction of a z-axis in a working volume (V) disposed on the z-axis about z=0, with a magnet coil system (A, A?, A?, A??) which comprises one or more superconducting magnet partial coil systems (A1, A1?, A1?, A1??, A2??, . . ., An??), each forming superconductingly short-circuited current paths in the operating state, and with a further coil system (C, C?, C?, C??) which can be charged or discharged independently of the magnet coil system (A, A?, A?, A??) and comprises a first and a second partial coil system (C1, C2, C1? C2?, C1?, C2?, C1??, C2??), wherein the first partial coil system (C1, C1?, C1?, C1??) and the second partial coil system (C2, C2?, C2?, C2??) each comprise at least one coil, wherein all coils of the further coil system (C, C?, C?, C??) are connected in series, wherein gCeff,diamag>0.1 mT/A, is characterized in that gC1eff,diamag>0.1 mT/A, gC2eff,diamag>0.Type: GrantFiled: May 6, 2008Date of Patent: July 28, 2009Assignee: Bruker Biospin AGInventors: Francesca Venturini, Robert Schauwecker, Pierre-Alain Bovier
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Publication number: 20090167304Abstract: Apparatus and method for varying field strength in a magnetic resonance system while keeping a relatively uniform magnetic field distribution. In an embodiment, a two-pole, generally u-shaped magnet assembly generates a static and uniform magnetic field. The magnet assembly includes two facing magnet poles separated by an air gap. Holes may be formed with the magnet poles. The field control rods may be placed at a pre-determined distance into these holes and symmetrically or asymmetrically moved across each magnet poles in a controlled manner to change the magnetic field strength while keeping the uniform magnetic field distribution. Maximum magnetic field strength may occur when the rods are removed. Minimum magnetic field strength may occur when the rods are fully inserted.Type: ApplicationFiled: December 28, 2007Publication date: July 2, 2009Inventors: Pablo J. PRADO, Sankaran Kumar, Erik Edmund Magnuson
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Patent number: 7554327Abstract: In a method for determination and evaluation of a shim parameter set for controlling a shim device in a magnetic resonance (MR) apparatus, the shim device is set using a first shim parameter set, a first field distribution is measured in a body region encompassing a target volume from which MR data are to be acquired, a second shim parameter set is determined using an algorithm for optimization of the field homogeneity in the target volume on the basis of the first shim parameter set and dependent on the first field distribution, a second field distribution is determined on the basis of the second shim parameter set, and the shim parameter sets are evaluated by indirect or direct comparison of the first field distribution and the second field distribution, in particular in the target volume.Type: GrantFiled: October 12, 2007Date of Patent: June 30, 2009Assignee: Siemens AktiengesellschaftInventors: Andrew Dewdney, Sabrina Harter
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Patent number: 7548061Abstract: In a method for determination or adaptation of a shim for homogenization of a magnetic field of a magnetic resonance apparatus, which magnetic field is provided for the generation of magnetic resonance exposures of a specific examination region, an automatic determination, of a computer and/or supported by an operator on an image output unit of the computer, is made of a three-dimensional volume that is relevant for the determination or adaptation of the shim and that is matched to the examination region and/or an examination protocol by selection from an arbitrary morphology set of selectable volumes (which morphology set is not limited to specific shapes) and/or by generation of an arbitrarily three-dimensional volume not limited to specific shapes. The computer then automatically calculates the shim for the determined or selected three-dimensional volume.Type: GrantFiled: February 26, 2008Date of Patent: June 16, 2009Assignee: Siemens AktiengesellschaftInventors: Andrew Dewdney, Franz Schmitt
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Patent number: 7548063Abstract: The present invention relates to a system and method magnetic resonance (MR) imaging. Furthermore the invention relates to the use of a material and to a computer program. In order to provide a technique which allows to prevent standing waves in an RF cage (3) of a MR imaging system (1) in a very cheap and simple way a MR imaging system (1) is suggested, which comprises a MR imaging apparatus (2) comprising an open magnet system (7), wherein operation of the MR imaging apparatus (2) creates a magnetic resonance field having a MR frequency, and which further comprises an RF cage (3), configured to enclose the MR imaging apparatus (2), wherein the walls (6) of the RF cage (3) are at least partly provided with a covering (5, 10), said covering (5, 10) is adapted in a way that the wavelength of the MR frequency within the covering (5, 10) is reduced.Type: GrantFiled: April 28, 2006Date of Patent: June 16, 2009Assignee: Koninklijke Philips Electronics N.V.Inventors: Cornelis Leonardus Gerardus Ham, Miha Fuderer, Marinus Ludovicus Adrianus Vrinten
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Patent number: 7543370Abstract: In a method for production of a superconducting magnetic coil, winding of superconducting wires of the superconducting magnetic coil is implemented with at least one UV-curable plastic, and the UV-curable plastic is at least partially cured with UV light during the winding. A magnetic resonance apparatus has a superconducting magnetic coil that is produced according to this method.Type: GrantFiled: March 30, 2007Date of Patent: June 9, 2009Assignee: Siemens AktiengesellschaftInventor: Gerhard Bittner
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Patent number: 7541811Abstract: A compact, lightweight, and easy-to-use ESR-CT apparatus including a magnetic field leak line (5-G line) which is capable of imaging a small animal, such as a mouse, within 15 minutes, and of observing a desired region with a spatial resolution of 1 mm or less. A permanent magnet system is introduced of the apparatus includes pole pieces having a predetermined area which are opposed to each other through a measured space, yokes combined with the pole pieces, and a permanent magnet inserted in series so that at least one magnetic pole plane intersects perpendicularly to the closed magnetic circuit for magnetic coupling with the yokes. This makes it possible to locate a gradient coil system and a field scanning coil system sufficiently apart from end faces of the pole pieces, and to downsize the field scanning coil system so that the gradient field system is movable.Type: GrantFiled: July 6, 2007Date of Patent: June 2, 2009Assignee: Hitachi, Ltd.Inventor: Toshiyuki Usagawa
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Patent number: 7541812Abstract: A magnetic resonance imaging apparatus includes a static magnetic field generating unit, a main coil (gradient magnetic coil), a radio frequency coil, and a shimming structure unit. The shimming structure unit includes first iron shims and second iron shims. The first iron shims are disposed between the main coil and a shield coil of the gradient magnetic coil and disposed in a central axial center of the static magnetic field generating unit. The second iron shims are disposed on an outer side of the main coil and the shield coil and disposed on a central axial end of the static magnetic field generating unit.Type: GrantFiled: January 31, 2008Date of Patent: June 2, 2009Assignees: Kabushiki Kaisha Toshiba, Toshiba Medical Systems CorporationInventor: Kazuto Nogami
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Patent number: 7538553Abstract: Magnetic structure for MRI machines, which machine has a U-shaped or annular, that is O-shaped geometry having two opposite poles between which a magnetic field is generated and are borne at a predetermined distance one with respect to the other by a magnetic yoke having an inverted U shape or an annular one, that is an O shape, which poles generating the magnetic field and/or at least a part of which yoke delimit a cavity housing at least a part of the patient body, while inside the volume of said cavity a partial volume is generated wherein values of the magnetic field are such to guarantee the acquisition of MRI images having quality characteristics sufficient to be used like diagnostic images, so called imaging volume. The invention relates also to a machine for detecting MRI images particularly of the anatomical region of the hand or the foot or part of joints and which machine has a magnetic structure of the type described above.Type: GrantFiled: February 19, 2008Date of Patent: May 26, 2009Assignee: Esaote S.p.A.Inventors: Alessandro Trequattrini, Stefano Pittaluga, Stefano Besio, Eugenio Biglieri
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Patent number: 7535229Abstract: Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.Type: GrantFiled: April 26, 2007Date of Patent: May 19, 2009Inventors: Ross D. Schlueter, Thomas F. Budinger
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Patent number: 7535231Abstract: In a method for adjustment of a shim device of a magnetic resonance apparatus before an image acquisition in a body region that has a volume of interest, a field distribution is measured in a region encompassing the volume of interest produced with a shim device set according to a basic shim data set. A shim data set that is optimized for the volume of interest is determined by a control device starting from the basic shim data set, dependent on the field distribution; and the optimized shim data set is used for adjustment of the shim device. The basic shim data set is selected from a databank of body region-specific input shim data sets.Type: GrantFiled: October 12, 2007Date of Patent: May 19, 2009Assignee: Siemens AktiengesellschaftInventors: Andrew Dewdney, Sabrina Harter, Franz Schmitt
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Publication number: 20090096453Abstract: In a method and an arrangement for shimming a cylindrical magnet system, that has a cylindrical magnet having a bore therein with an axis extending therethrough, and a gradient coil assembly located within the bore, shimming is accomplished by stacking a number of planar pieces of shim material in each of said tubes, with each of the tubes having an axis parallel to the axis of the cylindrical magnet, and with the planar pieces of shim material and stacked in the tubes in respective planes that are perpendicular to the axis fo the cylindrical magnet.Type: ApplicationFiled: July 5, 2007Publication date: April 16, 2009Inventors: Timothy Barnes, Benjamin John Catmull, John Hedley Toyer, Ian Wilkinson
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Patent number: 7518370Abstract: A vacuum vessel assembly includes an inner cylinder and an outer cylinder formed of a material in which eddy currents are substantially not produced. The inner cylinder includes a first and second half having an annular flange thereon. A plurality of metal interfaces are connected to the inner cylinder and the outer cylinder. The plurality of metal interfaces bond the first half and second half of the inner cylinder and also bond the inner cylinder to the outer cylinder.Type: GrantFiled: November 30, 2006Date of Patent: April 14, 2009Assignee: General Electric CompanyInventors: Xianrui Huang, Paul S. Thompson
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Patent number: 7514928Abstract: The invention concerns a magnet configuration comprising a superconducting magnet coil (1) within which a gradient system is to be switched. All low temperature oscillation systems (R1) with a temperature T1<10K within the magnet coil (1) are produced from a material having good electrical conducting properties, and at least one warm oscillation system (R2) with a temperature T2>10K within the magnet coil (1) has worse electrical conducting properties and has a considerably different mechanical resonance frequency (separation approximately 500 Hz or more) than at least one of the low temperature oscillation systems (R1). This reduces the undesired heating power supplied to the low temperature oscillation systems due to mechanical oscillations and induced eddy currents.Type: GrantFiled: April 12, 2007Date of Patent: April 7, 2009Assignee: Bruker Biospin GmbHInventor: Michael Westphal
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Patent number: 7511502Abstract: A magnetic resonance imaging apparatus includes a static magnetic field magnet which generates a static magnetic field, a gradient coil unit which generates a gradient magnetic field for overlapping with the static magnetic field, a shim unit which is disposed between the static magnetic field magnet and the gradient coil unit to control the static magnetic field, and a heat shielding member which is disposed between the gradient coil unit and the shim unit to shield a radiant heat of the gradient coil unit.Type: GrantFiled: December 18, 2007Date of Patent: March 31, 2009Assignees: Kabushiki Kaisha Toshiba, Toshiba Medical Systems CorporationInventors: Yoshitomo Sakakura, Masatoshi Hanawa
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Patent number: 7504826Abstract: A superconducting magnet of the present invention includes a switching element that closes its output side (operation side) when the voltage on its input side is smaller than a predetermined value and opens the output side when the voltage on the input side is larger than the predetermined value, wherein the input side is connected in parallel to a main coil circuit, and the output side of is connected in series to external magnetic-field disturbance compensation coils, for releasing the circuit of the disturbance compensation coil by closing the output side if the voltage on the input side is smaller than the predetermined value.Type: GrantFiled: February 8, 2007Date of Patent: March 17, 2009Assignee: Mitsubishi Electric CorporationInventor: Hajime Tanabe
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Patent number: 7501822Abstract: A magnetic resonance (MR) probe head comprises a detecting device with at least one antenna system which is cryogenically cooled by a cooling device, and a cooled preamplifier in a preamplifier housing which is spatially separated from the detecting device, and a thermally insulating connecting means via which the detecting device and the preamplifier housing are connected, wherein the connecting means comprises at least one cooling line for supplying and/or returning a cooling fluid, and with at least one RF line for transmitting the electric signals. The connecting means is implemented as a mechanically flexible connecting line with mechanically flexible RF lines and cooling lines disposed therein. The MR probe head is easy to handle and can be highly sensitive, wherein the detecting device can be quickly installed, removed and put into operation.Type: GrantFiled: April 4, 2007Date of Patent: March 10, 2009Assignee: Bruker Biospin AGInventors: Marco Sacher, Daniel Marek, Tobias Leutenegger, Daniel Guy Baumann, Ralf Haueisen
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Patent number: 7498811Abstract: The present invention relates, in general, to the field of motion tracking, and in particular to join a target in an MRI application. In particular the invention teaches an apparatus and method to track the movement of a target during medical imaging scanning using optical technology. Optical systems record the position and movement of the pattern and are able to perform mathematical analysis of the pattern to determine the positional shift of the patient. Weighted averages, Fourier transforms, Hadamard matrices and cross-correlation of data related to X-Y translation, rotation and scaling of the image of the pattern are used to analyze movement of the subject's head. Feedback related to the movement is provided to the MRI machine which allows for adjustments in focusing coils for real time tracking of the patient's movements during the MRI procedure. As a result, the MRI procedure becomes more accurate as it is adjusted for the patient's movements.Type: GrantFiled: November 16, 2005Date of Patent: March 3, 2009Inventors: Duncan L. MacFarlane, Richard Briggs, Andrei A. Zaremba, Keith D. White
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Patent number: 7498814Abstract: A magnet assembly for a Magnetic Resonance Imaging (MRI) system includes a vacuum vessel including an inner cylinder, an outer cylinder and a pair of tapered flanges connecting the inner and outer cylinders. The inner cylinder is made of a composite material. The outer cylinder and flanges are composed of several magnetic segments that provide a magnetic flux return path with low eddy currents. The segments are bonded together and electrically insulated from each other. A container, a thermal shield and a superconducting magnet coil assembly are disposed within the vacuum vessel. The superconducting magnet coil assembly includes a non-conductive cylindrical structure and superconducting coils. A thermally conductive cable is wrapped around the cylindrical structure and coils to form a thermally conductive envelope.Type: GrantFiled: October 31, 2007Date of Patent: March 3, 2009Assignee: General Electric CompanyInventors: Xianrui Huang, Minfeng Xu, Evangelos Trifon Laskaris, Paul St. Mark Shadforth Thompson, Bulent Aksel, Kathleen Melanie Amm, Anbo Wu, Yan Zhao
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Patent number: 7492158Abstract: A method for determining construction parameters of magnet structures designed to generate magnetic fields in predetermined volumes of space, comprising the steps of: a) defining a predetermined volume of space in which a static magnetic field is to be generated; b) defining the nominal strength and profile of the magnetic field in said predetermined volume of space; c) mathematically describing the nominal magnetic field on the surface of and/or in said predetermined volume of space by using a polynomial expansion of the magnetic field-describing function, which provides a series of coefficients; d) determining the size, geometry and relative position in space of the means for generating said nominal magnetic field, with respect to the volume of space in and on which the desired, i.e. nominal magnetic field, is defined.Type: GrantFiled: September 6, 2006Date of Patent: February 17, 2009Assignee: Esaote S.p.A.Inventors: Vincenzo Punzo, Stefano Pittaluga, Stefano Besio, Alessandro Trequattrini
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Patent number: 7482807Abstract: The invention relates to a method of determining a spatial distribution of magnetic particles in an examination zone, in which method a first magnetic field is generated, which forms in the examination zone a first sub-zone having a relatively low magnetic field strength and a second sub-zone having a relatively high magnetic field strength. The position in space of the two sub-zones is then changed by a second magnetic field, whereby the magnetization in the examination zone is changed. Signals dependent on the change in magnetization are acquired and evaluated to extract information concerning the spatial distribution of the magnetic particles. The second magnetic field is generated so that the time derivative of the second magnetic field is substantially identical for each spatial component.Type: GrantFiled: September 20, 2005Date of Patent: January 27, 2009Assignee: Koninklijke Philips Electronics N.V.Inventors: Bernhard Gleich, Juergen Weizenecker
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Patent number: 7479860Abstract: A magnetic field generating assembly comprising a set (A1-A3;B1-B3;C1-C3) of, typically substantially coaxial, coils substantially symmetrically arranged about a plane orthogonal to the axis. At least some of the coils carry working currents in the opposite sense to the other coils The arrangement of turns and working currents carried by the coils is such that a first working volume (10) with a substantially homogeneous magnetic field is generated within the envelope defined by the assembly, and two second working volumes (11) each with a substantially homogeneous magnetic field are generated outside the envelope, the homogeneity of each of the first and second working volumes being sufficient to perform a NMR experiment on a sample in the working volume.Type: GrantFiled: September 30, 2003Date of Patent: January 20, 2009Assignee: Oxford Instruments PLCInventors: Ian Leitch McDougall, Robert Andrew Slade, Peter Hanley, Robert Carter Hawkes
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Patent number: 7477055Abstract: A system and method for connecting superconducting magnet coils made up of coil segments to allow an integrated winding concept. The integrated winding concept can include serially connecting coil segments of coil pairs in an alternating pattern, which causes coil pairs to be electrically symmetric. Symmetric coil pairs can eliminate or significantly reduce the currents in magnet coils induced by gradient or other pulses, produce a homogenous field, and reduce the accumulated voltages in the coils due to gradient pulsing.Type: GrantFiled: August 21, 2007Date of Patent: January 13, 2009Assignee: General Electric CompanyInventors: Xianrui Huang, Paul S. Thompson, Minfeng Xu
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Patent number: 7468606Abstract: Disclosed is a vacuum housing for a magnetic resonance apparatus having a recess for leading through lead wires to elements located inside the vacuum housing, and a first lead-through bushing module. The first lead-through bushing module is provided with a first closing plate which is configured so as to vacuum-tightly seal the recess along with a second closing plate. The first bushing module is also provided with a first structural component that is to be at least partially led through the recess during assembly of the lead-through bushing module and whose size defines a minimum size of the recess, which is greater than the size of the first closing plate.Type: GrantFiled: January 17, 2005Date of Patent: December 23, 2008Assignee: Siemens AktiengesellschaftInventors: Eva Eberlein, Johann Schuster, Stefan Stocker
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Patent number: 7466133Abstract: Systems, methods and apparatus are provided through which in some embodiments a magnetic resonance imaging (MRI) system includes one or more magnetic shield coils positioned asymmetrically in the casing and also positioned in close proximity to one of two apertures of an inner bore of the MRI system. In those embodiments, the position of the one or more magnetic shield coils provides an asymmetric magnetic stray field during operation of the MRI system, which in turn allows operation of electronic medical diagnostic equipment or electronic medical monitoring equipment in close proximity to the MRI.Type: GrantFiled: March 1, 2005Date of Patent: December 16, 2008Assignee: General Electric CompanyInventors: Timothy John Havens, Stephen R. Elgin, Ricardo Becerra
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Publication number: 20080303523Abstract: In a magnetic resonance scanner, a main magnet system (10) is wound to generate a longitudinally directed main magnetic field (B0) at least in a scanning region (20). The main magnet system includes a central magnet winding region (30) wound layer-by-layer disposed between outer magnet winding regions (32, 34). A longitudinal magnetic field gradient system (12, 12?) includes a central gradient winding region (40, 40?, 42, 42?) wound to generate a main longitudinally directed magnetic field gradient disposed between outer gradient winding regions (44, 46) wound to generate a compensatory longitudinally directed magnetic field gradient having opposite polarity from the main longitudinally directed magnetic field gradient. The outer gradient winding regions are arranged to substantially null mutual inductance between the outer magnet winding regions (32, 34) and the longitudinal magnetic field gradient system (12, 12?).Type: ApplicationFiled: December 12, 2006Publication date: December 11, 2008Inventor: Johannes Overweg
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Publication number: 20080303522Abstract: There is provided a magnetic field generator 10 which is capable of generating a uniform magnetic field of a desired intensity easily and stably without increasing running cost. The magnetic field generator 10 includes a pair of plate yokes 12a, 12b. The plate yokes 12a, 12b have opposed surfaces provided with magnetic pole 14a, 14b respectively. The magnetic pole 14a includes a permanent magnet group 16a whereas the magnetic pole 14b includes a permanent magnet group 16b. Each of the permanent magnet groups 16a, 16b is formed substantially in a disc like shape, as an integral body made of a plurality of permanent magnets 20 and a plurality of heat conducting members 22. Tubular heaters 34, buried in the plate yokes 12a, 12b, generate heat, which is conducted via the plate yokes 12a, 12b to each permanent magnet 20 and each heat conducting member 22 which constitute the permanent magnet groups 16a, 16b.Type: ApplicationFiled: June 28, 2005Publication date: December 11, 2008Inventor: Masaaki Aoki
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Patent number: 7463029Abstract: A cooling apparatus for arrangement between two surface coils of a gradient coil to dissipate the heat produced when current is supplied to the surface coils by a coolant flowing into the cooling apparatus, is formed as a flexible, mat-type surface structure, and has a coolant-holding space with at least one coolant inflow and at least one coolant outflow.Type: GrantFiled: March 28, 2007Date of Patent: December 9, 2008Assignee: Siemens AktiengesellschaftInventors: Johann Schuster, Stefan Stocker
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Patent number: 7459908Abstract: A method of providing shim sheets for adjusting a magnetic field in a magnetic resonance device by passive shimming, comprises the steps of field mapping of a region of interest in the MR device for obtaining an uncorrected magnetic field distribution including field inhomogeneities, decomposing the field inhomogeneities into first and second order spherical harmonic functions, determining primary shim terms derived from the second order spherical harmonic functions, wherein the primary shim terms yield a passive shim field adapted to a targeted shim field, scaling optimized shim terms for increasing a similarity of the passive shim field with the targeted shim field, constructing modular shim sheets on the basis of the optimized shim terms, and mounting the modular shim sheets on a shim sheet carrier of the magnetic resonance device. Furthermore, an adjustment device for adjusting a magnetic field in a magnetic resonance device by passive shimming is described.Type: GrantFiled: September 5, 2006Date of Patent: December 2, 2008Assignee: Max-Planck-Gesellschaft zur Forderung der Wissenschaften E.V.Inventor: Christoph Juchem
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Patent number: 7453264Abstract: A magnet for a Magnetic Resonance Imaging apparatus, said magnet having at last two, preferably three open sides, and delimiting the patient receiving area, said magnet being composed of three yoke elements, i.e. two parallel magnetically permeable elements and one transverse yoke element for connection of said two parallel elements, whereby said magnet has a C shape and wherein, for both of said parallel elements, the terminal portion associated to said transverse connecting element has a transverse wall for connection of said two parallel elements with the transverse element, which has an end step for engagement of a corresponding end of said transverse element.Type: GrantFiled: March 25, 2005Date of Patent: November 18, 2008Assignee: Esaote, S.p.A.Inventors: Alessandro Trequattrini, Luigi Satragno, Eugenio Biglieri, Stefano Pittaluga
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Publication number: 20080224807Abstract: A magnet arrangement comprising a superconducting magnet coil system (M) for generating a magnetic field in the direction of a horizontal z-axis in a working volume (V) disposed along the z-axis about z=0 with at least one radial access to the working volume (V) perpendicular to the z-axis, wherein the magnet coil system comprises at least one partial coil winding (A1a, A1b) disposed coaxially about the z-axis at z>0, and at least one partial coil winding (B1a, B1b) disposed coaxially about the z-axis at z<0, is characterized in that at least one of the partial coil windings (A1a, A1b) at z>0 as well as at least one of the partial coil windings (B1a, B1b) at z<0 are supported by a common coil body (K1), wherein the coil body (K1) has at least one opening (O1) at z=0, which permits radial access to the working volume (V), wherein the coil body (K1) supports the axial magnetic forces between the partial coil windings and wherein the coil body is force-fit mechanically connected to a first side plateType: ApplicationFiled: March 13, 2008Publication date: September 18, 2008Inventors: Francesca Venturini, Patrick Mock, Robert Schauwecker
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Publication number: 20080217533Abstract: The present invention provides a charged particle spin polarimeter capable of resolving with high efficiency the magnetic moment of a charged particle. The charged particle spin polarimeter has a pair of convex and concave magnetic poles to apply a magnetic field with gradient to an incident charged particle and a pair of plain plate electrodes to apply, to a charged particle, an electric field for canceling a Lorenz force that the charged particle receives from the magnetic field. The magnetic moment in the magnetic field direction of a charged particle is resolved by the interaction between the gradient of the magnetic field and the magnetic moment of the charged particle.Type: ApplicationFiled: February 11, 2008Publication date: September 11, 2008Inventor: Teruo KOHASHI
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Patent number: 7423431Abstract: A permanent magnet assembly for an imaging apparatus having a permanent magnet body having a first surface and a stepped second surface which is adapted to face an imaging volume of the imaging apparatus, wherein the stepped second surface contains at least four steps.Type: GrantFiled: September 29, 2003Date of Patent: September 9, 2008Assignee: General Electric CompanyInventors: Kathleen Melanie Amm, Evangelos Trifon Laskaris, Paul Shadforth Thompson, Bulent Aksel, Bruce Campbell Amm, Michael Anthony Palmo, Jr, Johannes Martinus Van Oort, Xianrui Huang
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Patent number: 7420372Abstract: There is described a magnetic resonance device incorporating at least one first component part, which when the magnetic resonance device is operating oscillates, attached by at least one local load-bearing joint to at least one second oscillation-sensitive component part of the magnetic resonance device, where the joint has at least one actuatable facility for generating counter-oscillations which damp an oscillation of the first component part, where the second component part is a cladding element, in particular a vacuum cladding, which is affixed to the magnet via the joint, whereby a gap between the cladding element and the magnet is evacuatable, and the gap is provided with a pressure-isolating acoustically soft seal, in particular in the form of bellows.Type: GrantFiled: April 24, 2007Date of Patent: September 2, 2008Assignee: Siemens AktiengesellschaftInventors: Jürgen Nistler, Martin Rausch, Wolfgang Renz
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Publication number: 20080197850Abstract: In an arrangement of a basic field magnet and a gradient coil of a magnetic resonance apparatus, the basic field magnet includes superconducting coils that are arranged in a reservoir with liquid helium for cooling. The helium reservoir is surrounded by a further reservoir, designated as an outer vacuum chamber. A vacuum exists between the outer vacuum chamber and the helium reservoir. A cryoshield is arranged between the outer vacuum chamber and the helium reservoir. The gradient coil is arranged in the inner chamber of the basic field magnet. The cryoshield has additional structure for reinforcement that counteract vibrations of the cryoshield.Type: ApplicationFiled: February 21, 2008Publication date: August 21, 2008Inventors: Peter Dietz, Andreas Krug, Mark James Le Feuvre, Annette Lohfink, Thorsten Speckner
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Publication number: 20080197845Abstract: Magnetic structure for MRI machines, which machine has a U-shaped or annular, that is O-shaped geometry having two opposite poles between which a magnetic field is generated and are borne at a predetermined distance one with respect to the other by a magnetic yoke having an inverted U shape or an annular one, that is an O shape, which poles generating the magnetic field and/or at least a part of which yoke delimit a cavity housing at least a part of the patient body, while inside the volume of said cavity a partial volume is generated wherein values of the magnetic field are such to guarantee the acquisition of MRI images having quality characteristics sufficient to be used like diagnostic images, so called imaging volume. The invention relates also to a machine for detecting MRI images particularly of the anatomical region of the hand or the foot or part of joints and which machine has a magnetic structure of the type described above.Type: ApplicationFiled: February 19, 2008Publication date: August 21, 2008Applicant: ESAOTE S.p.A.Inventors: Alessandro TREQUATTRINI, Stefano Pittaluga, Stefano Besio, Eugenio Biglieri
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Publication number: 20080191823Abstract: A magnet coil system (2) which is at least partially superconducting at a cryogenic temperature, comprising at least two partial coils (3, 4, 5) which are connected in series and are each bridged by a superconducting switch (6, 7, 8), such that the partial coils form independent electric loops (11, 12, 13) when the superconducting switches (6, 7, 8) are closed, is characterized in that two electric loops (11, 12) have a common section and a flux pump (10) is provided which is circuited in the common section (14) of the electric loops (11, 12) of two partial coils (3, 4), wherein the sum of the currents of the two partial coils (3, 4) flows through the flux pump (10) in the operating state. In this fashion, the drifts of two independent electric loops can be compensated for with a few devices.Type: ApplicationFiled: February 1, 2008Publication date: August 14, 2008Inventors: Rolf Spreiter, Patrik Vonlanthen
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Patent number: 7408349Abstract: A configurable matrix receiver comprises a plurality of antennas that detect one or more signals. The antennas are coupled to a configurable matrix comprising a plurality of amplifiers, one or more switches that selectively couple the amplifiers in series fashion, and one or more analog-to-digital converters (ADCs) that convert the output signals generated by the amplifiers to digital form. For example, in one embodiment, a matrix comprises a first amplifier having a first input and a first output, and a second amplifier having a second input and a second output, a switch to couple the first output of the first amplifier to a the second input of the second amplifier, a first ADC coupled to the first output of the first amplifier, and a second ADC coupled to the second output of the second amplifier. In one embodiment, the signals detected by the antennas include magnetic resonance (MR) signals.Type: GrantFiled: December 15, 2005Date of Patent: August 5, 2008Assignee: Fonar CorporationInventor: David Hertz