摘要:
A resonator for magnetic resonance applications has a conductor element that extends from a first conductor end to a second conductor end. During operation of the conductor element at a resonance frequency, a resonance current-oscillates from the first conductor end to the second conductor end and back. The conductor ends are coupled with one another via a circuit that tunes the conductor element to the resonance frequency. The conductor element is fashioned as a multi-layer conductor with a number of layers that have first and second layer ends at the conductor ends. The circuit causes layer currents that are of equal magnitudes to flow in the layers themselves during active operation of the conductor element at the resonance frequency.
摘要:
A selection unit for a magnetic resonance imaging system may be provided. The selection unit electrically connects a first number of electrical terminals to a second number of communication entities. The selection unit is arranged in and/or on a mobile object-support element for moving an examination object which is to be depicted by the magnetic resonance imaging system into a recording position.
摘要:
A circulator has a ferrite, and the circulator is arranged in the vicinity of a device that produces a static magnetic field in the environment surrounding the device, this static magnetic field giving the circulator a non-reciprocal behavior, with respect to circulation of energy among the gates of the circulator, as a result of interaction of the ferrite with the static magnetic field. A magnetic resonance apparatus embodies such a circulator, and the basic field magnet of this magnetic resonance apparatus generates the static magnetic field.
摘要:
A resonator for magnetic resonance applications has a conductor element proceeding in an extension direction, that operates with a resonance current at a resonance frequency oscillating therein in the extension direction. The conductor element is tuned to the resonance frequency and has an overall length in the extension direction that is smaller than half of the wavelength of the resonance frequency. The conductor element is a multi-layer conductor with layers that are electrically insulated from each other that, in said extension direction, have layer ends that are capacitively coupled with each other. During operation of the conductor element at the resonance frequency, respective layer currents flow in the layers in the extension direction that are substantially equal in magnitude.
摘要:
A magnetic resonance system has multiple individual transmission antennas each charged with a transmission current to emit an individual excitation field in an examination volume to excite magnetic resonances in a subject in the examination volume, with a total excitation field being a superimposition of the individual excitation fields. A determination device is provided with a spatial distribution of an absorption rate of the examination subject and determines a combination of amplitudes and phase positions for the transmission currents relative to one another such that a locally absorbed power at a first point of the examination subject relative to a locally absorbed power at a second point of the examination subject satisfies a relative condition. The determination device communicates the combination of amplitudes and phase positions that it has determined to a control device. The control device charges the transmission antennas with transmission currents whose phase positions correspond with the phase positions communicated by the determination device and whose amplitudes are scaled with a uniform scaling factor for all transmission currents relative to the amplitudes communicated by the determination device.
摘要:
An amplifier device for a mode antenna has a number of amplifiers and a number of outputs. An input signal is fed to each amplifier, which is amplified by the respective amplifier into an amplified input signal. The amplified input signals are fed to an output matrix arranged after the amplifiers. Respective output signals are emitted by the output matrix at the outputs. The output matrix causes each amplified input signal to supply an output signal contribution for each output signal. Each output signal contribution of each output signal has an output-side contribution offset in relation to the corresponding amplified input signal, which depends on the amplified input signal that supplied the output signal contribution, and the output signal to which the output signal contribution contributes. The amplifier device is especially able to be used in a transmit arrangement for radio-frequency signals.
摘要:
A generator device for a magnetic resonance excitation signal has a signal divider that divides an input signal supplied to it via an input element into at least two sub-signals and supplies them to amplification stages. The amplification stages amplify the respective sub-signals to produce amplified signals and supply the amplified signals to a signal combiner that combines them to form an aggregate signal, which is made externally available via an output element. Sensor devices that precede the signal divider and the signal combiner, acquire a reference signal that corresponds to the input signal and actual signals that correspond to the amplified signals and supply them to a control device. The control device acts on at least one of the amplification stages to cause the amplified signals to exhibit a predetermined amplitude ratio and a predetermined phase relation relative to one another.
摘要:
A generation device for a magnetic resonance excitation signal has a signal divider that divides an input signal supplied to it via an input element into at least two sub-signals and supplies them to amplification stages. The amplification stages amplify the respective sub-signals to produce signals and supply the amplified signals to a signal combiner that combines them to form an aggregate signal, which is made externally available via an output element. Sensor devices that precede the signal divider and the signal combiner, acquire a reference signal that corresponds to the input signal and actual signals that correspond to the amplified signals and supply them to a control device. The control device acts on at least one of the amplification stages to cause the amplified signals to exhibit a predetermined amplitude ratio and a predetermined phase relation relative to one another.
摘要:
In a transmission arrangement for a magnetic resonance apparatus, a high-frequency input signal, via an input terminal is supplied to a high-frequency power amplifier. The amplifier amplifies the input signal with from a high-frequency output signal and supplies it to an antenna arrangement that emits it as a magnetic resonance excitation signal. Directional couplers are respectively connected between the input terminal and the amplifier and between the amplifier and the antenna arrangement. The acquired signals are supplied to an amplitude controller that drives an amplitude regulator preceding the high-frequency power amplifier.
摘要:
An amplifier device for a mode antenna has a number of amplifiers and a number of outputs. An input signal is fed to each amplifier, which is amplified by the respective amplifier into an amplified input signal. The amplified input signals are fed to an output matrix arranged after the amplifiers. Respective output signals are emitted by the output matrix at the outputs. The output matrix causes each amplified input signal to supply an output signal contribution for each output signal. Each output signal contribution of each output signal has an output-side contribution offset in relation to the corresponding amplified input signal, which depends on the amplified input signal that supplied the output signal contribution, and the output signal to which the output signal contribution contributes. The amplifier device is especially able to be used in a transmit arrangement for radio-frequency signals.