摘要:
The invention relates to a method for compensating for a magnetic field disturbance affecting a magnetic resonance device, whereby the magnetic field disturbance is caused by a deflection of a component of the magnetic resonance device. To this end, the deflection or a variable causing the deflection is acquired in timed-dependent fashion, a mathematical field disturbance model is provided which models the effect the of the deflection on the magnetic field, and the acquired deflection or the variable causing the deflection is converted by means of the field disturbance model into a control variable for a compensation magnetic field generator or a high-frequency antenna. The compensation magnetic field generator controlled in this manner generates, for example, a compensation magnetic field which compensates for the magnetic field disturbance. The high-frequency antenna controlled in this manner is, for example, matched in its mid frequency to the magnetic field disturbance.
摘要:
In a gradient coil device having at least one conductor structure for use in a magnetic resonance apparatus, the conductor structure is a conductive liquid, contained in a tube system, that flows through the tube system in order to carry off heat lost during the operation of the gradient coil device.
摘要:
A cylindrical gradient coil arrangement is provided for a magnetic resonance device. The arrangement includes at least one conductive structure that forms at least one gradient coil and a cooling device that uses a cooling fluid to cool the at least one conductive structure. The arrangement includes an outer carrier structure and an inner carrier structure. The outer carrier structure includes two tubular, coaxial outer sections with different diameters. The inner, tubular carrier structure is arranged between and coaxially with the outer sections. The conductive structure is placed on the inner carrier structure. The inner carrier structure is spaced from the outer sections by a clearance. The clearance forms a cooling channel through which the cooling fluid of the cooling device may flow. The inner carrier structure is fastened to the outer carrier structure at least in a point-by-point manner.
摘要:
In a gradient coil and a method to manufacture a gradient coil for a magnetic resonance apparatus, the gradient coil has at least one saddle coil, the saddle coil having a spatially shaped, electrically conductive plate with a line-shaped recess penetrating the plate. Conductor structures that create a gradient magnetic field in an examination region when a current signal flows therethrough are formed by the recess and by the shaping of the plate. The recess is filled with an electrically insulating material before implementation of the spatial shaping.
摘要:
An assembly for magnetic field generation in a magnetic resonance tomography apparatus has a device for generation of a basic magnetic field, a vacuum vessel surrounding the basic field device and a device for generation of at least one gradient magnetic field. The assembly has a volume with a reduced magnetic field strength in a region between windings of at least one superconducting coil of the basic field device and a non-conductive wall of the vacuum vessel. The gradient field device is fashioned as a superconductor and is at least partially accommodated in this volume.
摘要:
Magnetic resonance device comprising a preferably essentially cylindrical vacuum housing containing a magnet together with a cooling device, said vacuum housing having an inner wall, an outer wall and two end walls, the inner wall and/or one or each end wall being fashioned as a composite component consisting of one or more components made of a non-metallic composite material and a plurality of metal components serving to provide mechanical reinforcement and having a lamellar or annular form for forming the inner wall or having the form of a segment of a circle for forming an end wall such that a reduction in eddy currents is produced.
摘要:
In a method for calculating conductor tracks of a gradient coil in a gradient coils for a magnetic resonance tomography apparatus and a magnetic resonance tomography apparatus employing such a gradient coil system, conductor tracks are calculated for a primary coil with multiple conductor bundles, and for a second coil which shields the primary coil, as well as for at least one booster coil that is interconnected with the conductor bundles of the primary coil, and with the secondary coil, so that a number of different homogeneity volumes can be produced at the center of the gradient coil system.
摘要:
In a method for operating a magnetic resonance tomography device having a gradient system, which contains at least one gradient coil arrangement for generating a gradient field in a spatial direction and which also contains an energy supply device that is connected to the gradient coil arrangement, and wherein the gradient coil arrangement has at least one first sub-coil and one second sub-coil, and wherein the energy supply device is fashioned such that currents can be adjusted independently of one another in the sub-coils for the continuous adjustment of at least one property of the gradient field, the current in at least one of the sub-coils is determined and adjusted by solving an optimization task containing a target function and at least one secondary condition so that stimulations of a living examination subject are avoided.
摘要:
A patient couch for a magnetic resonance tomography system and a magnetic resonance tomography system are provided. The patient couch includes a feed facility for radiofrequency energy having a plurality of conduction paths for feeding radiofrequency energy. The patient couch also includes a plurality of plug-in connectors for local coils having a transmit coil, and a distribution structure for the distribution of radiofrequency energy from the feed facility to the plug-in connectors.
摘要:
A method and a magnetic resonance tomography (MRT) system are provided. The MRT system includes a controller configured to store a transmit vector that is established on a local-coil-specific basis. The transmit vector, for a specific local coil, indicates with which amplitudes and phases, transmit elements of the local coil may be controlled by a transmit device. The controller is configured to initiate a patient-specific calibration measurement on a patient to generate patient-specific calibration data representing a field distribution. The controller is also configured to determine deviations in the patient-specific calibration data from the stored transmit vector established on a local-coil-specific basis. The patient-specific calibration data is generated in the patient-specific calibration measurement on the patient and represents a field distribution. An imaging MRT measurement is not allowed if deviations exceed a threshold value, but is otherwise performed and is monitored by a monitoring device.