METHOD AND APPARATUS FOR SHUTTING DOWN A SUPERCONDUCTING MAGNET OF A MAGNETIC RESONANCE DEVICE

In a method and system for shutting down a superconducting magnet of a magnetic resonance apparatus using a monitoring processor and an energy store, the monitoring processor determines stored energy stored in the energy store at a first point-in-time, and determines a ramp energy required for shutting down, and determines a second point-in-time based on the stored energy and the ramp energy. At the second point-in-time, shutting down of the superconducting magnet is begun.

Methods for adjusting a magnetic field of a magnetic resonance tomography device, magnetic power supplies, and magnetic resonance tomography devices

A method for adjusting a magnetic field of a magnetic resonance tomography (MRT)-device having a magnet includes: transferring the magnet from an operating state to a non-operating state in a ramp-down mode; subsequently transferring the magnet from the non-operating state to the operating state in a ramp-up mode; observing a reference parameter different from the magnetic field; setting a target value for the reference parameter; comparing the observed reference parameter to the target value; and finishing the ramp-up mode when the reference parameter reaches the target value.

Magnetic resonance apparatus and operating method with recognition and avoidance of excessive excitations in an interference spectrum

In a magnetic resonance apparatus and an operating method therefor, at least one limitation criterion, which describes the avoidance of excessive excitations in an interference spectrum in the magnetic resonance scanner of the apparatus, formed by an interference frequency or an interference frequency range, is specified by a limitation supply processor in order to check a scanning protocol, described by recording parameters, that is to be implemented. At least part of the temporal control sequence of the scanning protocol is determined as a pre-calculation sequence from the recording parameters by a simulation processor and the pre-calculation sequence is checked in a checking processor by the limitation criterion. Implementation of the scanning protocol is prevented when the limitation criterion is not fulfilled.

Method and apparatus for shutting down a superconducting magnet of a magnetic resonance device

In a method and system for shutting down a superconducting magnet of a magnetic resonance apparatus using a monitoring processor and an energy store, the monitoring processor determines stored energy stored in the energy store at a first point-in-time, and determines a ramp energy required for shutting down, and determines a second point-in-time based on the stored energy and the ramp energy. At the second point-in-time, shutting down of the superconducting magnet is begun.

MAGNETIC RESONANCE APPARATUS AND METHOD FOR THE OPERATION THEREOF

In a magnetic resonance apparatus and an operating method therefor, at least one limitation criterion, which describes the avoidance of excessive excitations in an interference spectrum in the magnetic resonance scanner of the apparatus, formed by an interference frequency or an interference frequency range, is specified by a limitation supply processor in order to check a scanning protocol, described by recording parameters, that is to be implemented. At least part of the temporal control sequence of the scanning protocol is determined as a pre-calculation sequence from the recording parameters by a simulation processor and the pre-calculation sequence is checked in a checking processor by the limitation criterion. Implementation of the scanning protocol is prevented when the limitation criterion is not fulfilled.

Thermal Bus Structure for a Magnetic Resonance Imaging Device

A magnetic resonance imaging device including a main magnet, a gradient system with at least one gradient coil, a cryocooler, a thermal bus structure, and an electromagnetic shield arranged between the gradient system and the main magnet. The electromagnetic shield includes spaced shield elements. The electromagnetic shield is configured to provide an electromagnetic shielding of the main magnet from a magnetic field generated by the at least one gradient coil. The thermal bus structure includes thermal bus elements configured to provide a thermal connection between the plurality of spaced shield elements and a cold head of the cryocooler. At least two thermal bus elements of thermal bus elements include different heat transfer properties to provide individualized temperature control of the spaced shield elements.

Thermal Bus Structure for a Magnetic Resonance Imaging Device

The disclosure relates to a magnetic resonance imaging device comprising a main magnet, a gradient system including at least one gradient coil, a thermal bus structure, a shield structure arranged between the gradient system and the main magnet and a cryocooler including a cold head, wherein the shield structure is configured to reduce a transport of heat energy to the main magnet and wherein the main magnet comprises a magnet spacer configured for spacing individual coils of the main magnet, wherein the thermal bus structure comprises at least one thermal bus element extending through the magnet spacer for providing a thermal connection between the cold head of the cryocooler and the shield structure.

METHODS FOR ADJUSTING A MAGNETIC FIELD OF A MAGNETIC RESONANCE TOMOGRAPHY DEVICE, MAGNETIC POWER SUPPLIES, AND MAGNETIC RESONANCE TOMOGRAPHY DEVICES

A method for adjusting a magnetic field of a magnetic resonance tomography (MRT)-device having a magnet includes: transferring the magnet from an operating state to a non-operating state in a ramp-down mode; subsequently transferring the magnet from the non-operating state to the operating state in a ramp-up mode; observing a reference parameter different from the magnetic field; setting a target value for the reference parameter; comparing the observed reference parameter to the target value; and finishing the ramp-up mode when the reference parameter reaches the target value.

Combined shim and bore cooling assembly

For shimming a background magnetic field of a magnetic resonance imaging apparatus having an outer vacuum chamber (OVC) bore tube, a shimming arrangement has rails on the OVC bore tube and shim trays are mounted between respective rails.

METHOD AND APPARATUS FOR COMPENSATING FOR DRIFT IN MAGNETIC FIELD STRENGTH IN SUPERCONDUCTING MAGNETS

An MRI system has a cylindrical superconducting magnet assembly contained in a bore tube of a cylindrical vacuum vessel (OVC), and a gradient coil assembly situated within the OVC bore tube. In an imaging region within a bore of the gradient coil assembly, the magnet assembly produces a magnetic field that is subject to drift during operation of the MRI system. Compensating material is located at a radial position between the imaging region and the magnet in a location that will be heated over a range of temperatures during operation of the MRI system. The compensating material is adjustable between two magnetic phases in response to an applied physical characteristic, which is selectively applied thereto so as to change the compensating material from a first magnetization to a second magnetization, and thereby compensate the drift. 1. A magnetic resonance imaging (MRI) system comprising:a cylindrical superconducting magnet assembly having a longitudinal axis;a cylindrical vacuum vessel (OVC) having a bore tube therein, that contains the superconducting magnet assembly, said OVC having a bore tube therein that is rotationally symmetrical about the longitudinal axis;a gradient coil assembly situated within the bore tube of the OVC, said gradient coil assembly having a coil assembly bore therein;said superconducting magnet assembly being configured to produce a magnetic field in an imaging region within said bore tube of said gradient coil assembly, said magnetic field in said imaging region exhibiting a field property that is subject to drift due to heating that occurs during operation of said MRI system;compensating material situated at a radial position, relative to said longitudinal axis, between the imaging region and the superconducting magnet assembly at a location that is subject to heating over a range of temperatures due to said heating that occurs during said operation of the MRI system;said compensating material being adjustable between two magnetic phases ...

COMBINED SHIM AND BORE COOLING ASSEMBLY

An arrangement for shimming a background magnetic field of a magnetic resonance imaging apparatus having an outer vacuum chamber (OVC) bore tube (). Rails () are provided on the OVC bore tube and shim trays () are mounted between respective rails. 2. An arrangement according to wherein the shim trays are mounted to slide along a length of the rails and wherein the arrangement comprises a fixing arrangement that holds the shim tray in a desired position along the length of the rails.3. An arrangement according to wherein at least one shim tray comprises a ferromagnetic or paramagnetic material.4. An arrangement according to wherein each the shim tray comprises a bottom piece and a lid that is secured to the bottom piece.5. An arrangement according to wherein each shim tray has respective edges each having a lateral lip claim 1 , with the grooves retaining the shim trays by the lateral lips.6. An arrangement according to wherein at least one of the rails comprises a ferromagnetic or paramagnetic material.7. An arrangement according to wherein the coolant circuit comprises a cooler.8. An arrangement according to wherein the coolant circuit comprises a circulator.9. An arrangement according to wherein multiple arrangements of shim trays retained by said rails are located adjacent one another around the cylindrical OVC bore tube.10. An arrangement according to wherein each rail has respective grooves therein claim 9 , which each hold a respective edge of each of two adjacent shim trays.11. An arrangement according to wherein each rail has respective grooves therein claim 9 , which each hold a respective lateral lip of each of two adjacent shim trays.12. An arrangement according to wherein the shim trays and rails extend around the OVC bore tube claim 9 , forming a thermal shield for the OVC bore tube. The present invention concerns a combined shim and bore cooling assembly for a magnetic resonance imaging apparatus.In a magnetic resonance imaging (MRI) apparatus, the ...

Methods and apparatus for compensating for drift in magnetic field strength in superconducting magnets

Thermal bus structure for a magnetic resonance imaging device

The invention relates to a magnetic resonance imaging device (11) comprising a main magnet (17), a gradient system (19) including at least one gradient coil, a thermal bus structure (31), a shield structure (12) arranged between the gradient system (19) and the main magnet (17) and a cryocooler (32) including a cold head, wherein the shield structure (12) is configured to reduce a transport of heat energy to the main magnet (17) and wherein the main magnet (17) comprises a magnet spacer configured for spacing individual coils of the main magnet (17), wherein the thermal bus structure (31) comprises at least one thermal bus element extending through the magnet spacer for providing a thermal connection between the cold head of the cryocooler (32) and the shield structure (12).

Thermal bus structure for a magnetic resonance imaging device

The invention relates to a magnetic resonance imaging device (11) comprising a main magnet (17), a gradient system (19) with at least one gradient coil, a cryocooler (32), a thermal bus structure (31) and an electromagnetic shield (12) arranged between the gradient system (19) and the main magnet (17), wherein the electromagnetic shield (12) comprises a plurality of spaced shield elements and wherein the electromagnetic shield (12) is configured to provide an electromagnetic shielding of the main magnet (17) from a magnetic field generated by the at least one gradient coil, wherein the thermal bus structure (31) comprises a plurality of thermal bus elements configured to provide a thermal connection between the plurality of spaced shield elements and a cold head of the cryocooler (32) and wherein at least two thermal bus elements of the plurality of thermal bus elements comprise different heat transfer properties for providing an individualized temperature control of the plurality of spaced shield elements.

Verfahren zum Betrieb einer Magnetresonanzeinrichtung, Magnetresonanzeinrichtung, Computerprogramm und elektronisch lesbarer Datenträger

Verfahren zum Betrieb einer Magnetresonanzeinrichtung (1), bei dem zur Überprüfung eines durchzuführenden, durch Aufnahmeparameter beschriebenen Messprotokolls seitens einer Limitationsbereitstellungseinheit (14) wenigstens ein das Vermeiden zu starker Anregungen in einem durch wenigstens eine Störfrequenz oder einen Störfrequenzbereich gebildeten Störspektrum in der Magnetresonanzeinrichtung (1) beschreibendes Limitationskriterium vorgegeben wird, seitens einer Simulationseinheit (12) aus den Aufnahmeparametern als Vorausberechnungsablauf wenigstens ein Teil des zeitlichen Steuerablaufs des Messprotokolls ermittelt wird und der Vorausberechnungsablauf in einer Überprüfungseinheit (13) durch das Limitationskriterium geprüft wird, wobei bei nicht erfülltem Limitationskriterium eine Ausführung des Messprotokolls verhindert wird.