Koninklijke Philips Corporation N.v.

Philips Gmbh

Gerardus Bernardus Jozef Mulder

Philip Alexander Jonas

Johannes Adrianus Overweg

Philippe Abel Menteur

Jan Konijn

Johannes Ferdinand Van Der Koijk

Xianrui Huang

Cornelis Leonardus Gerardus Ham

Glen George Pfleiderer

Viktor Mokhnatyuk

Michael Leslie Allitt

Christoph G Leussler

Miha Fuderer

Paul Royston Harvey

Thomas Erik Amthor

Peter Forthmann

Derk Reefman

James Howard Kralick

Gerardus Nerius Peeren

Matthew Voss

Martijn Krelis Termeer

Paul Bernard Bunk

Joshua Kent Hilderbrand

Theo Jenneskens

Xiandrui Huang

Guus Van Hest

Christoph Leussler

A cryogenic cooling system () comprising a cryostat (), a two-stage cryogenic cold head () and at least one thermal connection member () that is configured to provide at least a portion of a heat transfer path () from the second stage member () to the first stage member () of the two-stage cryogenic cold head (). The heat transfer path () is arranged outside the cold head (). A thermal resistance of the provided at least portion of the heat transfer path () at the second cryogenic temperature is larger than a thermal resistance of the provided at least portion of the heat transfer path () at the first cryogenic temperature.

Cryogenic cooling system with temperature-dependent thermal shunt

A gradient coil assembly for a magnetic resonance imaging system () includes at least one gradient coil () and a cooling arangement for cooling the gradient coil (). The gradient coil () includes a solid electrical conductor material forming one or more conductor lines () which are in direct contact with each other. The cooling arrangement includes a cooling channel () for guiding a cooling fluid (). The cooling channel () is arranged outside along the one or more conductor lines () in such a way that in a cross-sectional view one single continuous interface line between the cooling channel () and the one or more conductor lines () is formed. In this way efficient cooling of the gradient coil () may be achieved.

Cooling a gradient coil of a magnetic resonance imaging system

A superconducting magnet includes superconducting magnet coils (C, C, C, C, C, C, S, S) disposed inside a magnet cryostat (). The superconducting magnet coils generate a static (B) magnetic field when an electric current flows in the superconducting magnet coils. A superconducting Bcompensation circuit () is also disposed inside the magnet cryostat, and is coupled with the superconducting magnet coils to passively reduce temporal variations in the Bmagnetic field generated by the superconducting magnet coils. An electric current sensor () is also disposed inside the magnet cryostat and is connected to measure electric current flowing in the superconducting Bcompensation circuit. An active Bcompensation component () is operatively connected with the electric current sensor to receive the measurement of electric current flowing in the superconducting Bcompensation circuit and to provide active Bmagnetic field compensation based on the measured electric current.

Cryogenic field sensing for compensating magnetic field variations in magnetic resonance imaging magnets

An apparatus includes an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault (e.g. a power loss to the compressor of a cryocooler) exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.

System and method for automatically ramping down a superconducting persistent magnet

An apparatus includes at least a first electrically conductive coil having at least first and second coil sections which are separated and spaced apart from each other, and a support structure disposed to support the first and second coil sections. The support structure, and an associated method of supporting the electrically conductive coil, maintain relative axial positions of the first and second coil sections to be fixed when the first electrically conductive coil is energized and de-energized, and allow each of the first and second coil sections to expand radially when energized.

Superconducting coil support device and method and apparatus including superconducting coil support device

A superconducting magnet device (), including at least one coil winding (-) of superconducting wire, configured for generating a static magnetic field B, wherein the at least one coil winding (-) is adapted to establish a thermally conductive contact with a cold head () of a cryocooler that is configured for bringing to and keeping the at least one coil winding (-) at a temperature below the critical temperature, and at least one gas-tight container () that permanently contains an amount of helium, wherein the at least one gas-tight container () is in thermally conductive contact to the at least one coil winding (-) for taking up thermal energy from the at least one coil winding (-) in at least one operational state; and a magnetic resonance imaging system () that is configured for acquiring magnetic resonance images from at least a portion of a subject of interest (), comprising such a superconducting magnet device () for generating a static magnetic field Bin an examination space () of the magnetic resonance imaging system ().

Superconducting magnet with cryogenic thermal buffer

The present invention relates to a magnetic resonance imaging system comprising a main magnet (), the main magnet () comprising a magnet bore, the bore having a longitudinal axis () parallel to the main magnetic field of the main magnet (), the magnet bore comprising a gradient coil system, wherein the gradient coil system comprises a first () satellite coil and an inner coil (), wherein the first satellite coil comprises at least one pair of saddle coils () arranged oppositely over the magnet bore and wherein the inner coil () comprises at least two pairs of saddle coils () arranged oppositely over the magnet bore, wherein the inner coil () is located at a larger diameter from the central axis () than the first () satellite coil, wherein the first satellite coil and the inner coil form a stepped coil structure.

Magnetic resonance imaging system with satellite gradient coils

The invention relates to a magnetic resonance imaging system () comprising: a main magnet () for generating a uniform, steady magnetic field within an examination volume, at least one RF antenna () for transmitting RF pulses to the examination volume for magnetic resonance spin excitation, a gradient coil unit comprising gradient coils () for generating gradient magnetic fields in the examination volume (), an RF shield () disposed between said RF antenna () and said gradient coils (), said RF shield () comprising a shielding material adapted for suppressing Eddy currents induced in the shield by said gradient magnetic fields and for screening RF fields towards the gradient coils (), said RF fields being generated by the RF antenna (), wherein the RF shield comprises a conductive coating () as shielding material.

RF shield for MRI comprising conductive coating as shielding material

A tesseral shim coil for shimming the magnetic field of a magnetic resonance system by generating the spherical harmonics of the sine and cosine type of the magnetic field, the tesseral shim coil comprising at least four saddle coils, wherein the sum of the azimuthal span of the at least four saddle coils is less than 360 degrees. First and second sets of shim coils, respectively generating sine and cosine components of the shim fields are combined into a single coil layer, thereby reducing the radial thickness of the shim coil assembly.

Tesseral shim coil for a magnetic resonance system

A magnetic resonance examination system includes a main magnet with superconducting coils to generate a main magnetic field and a gradient system to apply a gradient magnetic field superposed on the main magnetic field. A cooling system cools the superconducting coils to below their critical superconductivity temperature. A transfer monitor assesses the transfer of energy from the gradient system to the cooling system. The transfer monitor is configured to measure pressure changes in the cooling system. This leads to a simple manner of evaluating the transfer of energy from the gradient coils into the cooling system.

Magnetic resonance system with cooling system and monitoring of helium pressure

A magnetic resonance imaging (MRI) system having an open superconducting magnet system () includes a number of horizontally oriented superconducting coils () in a cryogenic container (). The cryogenic container contains a liquid cooling medium for cooling the superconducting coils which are located within the cryogenic container. At its top, the cryogenic container is provided with a recondensor () for continuously liquefying the cooling medium. The magnet system has a circuit for guiding the liquid cooling medium from the recondensor along at least part of the superconducting coils.

Cooling of a MRI system

Gradient fields G &equals;&part;B /&part;x etc. are generated in an MRI apparatus in order to indicate the position (x, y, z) of an object pixel to be imaged. In a known MRI system the x and y gradient fields are generated by a combination of four gradient coils, two of which are intended to receive the x and y gradient signals whereas the other two coils are intended to receive a mix of the x and y gradient signals in order to enable a simpler structure of the gradient coils and easier impedance matching. According to the invention, apart from the x, y and z gradient signals, other signals are applied to a conversion system ( ) in order to realize the desired gradient fields but also to achieve degrees of freedom that can be used for optimizing system parameters such as heat dissipation or the uniformity of the distribution of power among the gradient amplifiers.

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Eindhoven, Netherlands

Gerardus Bernardus Jozef Mulder