摘要:
In an active electrical device with an electrical line for operation in the examination volume of a nuclear spin tomography device, a sheath wave trap tuned to the operating frequency of the nuclear spin tomography device is installed in the line.
摘要:
The present embodiments relate to a device and a method for attenuating a high-frequency field of a magnetic resonance tomography system, where at least one attenuation element attenuating high-frequency fields is provided outside a magnetic resonance tomography field of view.
摘要:
A waveguide antenna assembly for a magnetic resonance tomography apparatus, particularly a waveguide antenna assembly that can be detuned for an operation with local coils, is composed of multiple metal surfaces connected by diodes respectively located between the metal surfaces. Only when the diodes are through-connected between these metal surfaces are the surfaces connected with one another in terms of RF signals via these diodes, so the assembly operates as a waveguide antenna. When the diodes are disabled between these metal surfaces, the surfaces are unconnected with one another for RF signals.
摘要:
A method provides for inputting and storing data for a clinical study in a uniform manner by different study locations. Accordingly, the method comprises generation of an input platform program for an input of data of a clinical study, distribution of the input platform to input locations, calling up and activating the input platform program dependent on a participant characteristic linked with a study participant in the clinical study, inputting the data at an input location via an input platform generated by the input platform program, and storing the input data.
摘要:
A magnetic resonance tomography system is provided having a multichannel transmission system for generating signals to be transmitted for multiple transmit channels. The system includes devices for decoupling signals of different transmit channels from a transmit chain and applying signals decoupled from the transmit chain at inputs of a Butler matrix. The system includes a Butler matrix configured such that a combination of signals of different transmit channels applied at its inputs occurs such that the amplitude of Butler matrix output signals at outputs of the Butler matrix is a function of the relative phases that the phases of signals of different transmit channels have relative to each other at inputs of the Butler matrix. The Butler matrix output signals are applied at inputs of a monitoring unit configured to determine the relative phases of the signals on a basis of amplitudes of the Butler matrix output signals.
摘要:
The present embodiments relate to a device and a method for attenuating a high-frequency field of a magnetic resonance tomography system, where at least one attenuation element attenuating high-frequency fields is provided outside a magnetic resonance tomography field of view.
摘要:
A waveguide antenna assembly for a magnetic resonance tomography apparatus, particularly a waveguide antenna assembly that can be detuned for an operation with local coils, is composed of multiple metal surfaces connected by diodes respectively located between the metal surfaces. Only when the diodes are through-connected between these metal surfaces are the surfaces connected with one another in terms of RF signals via these diodes, so the assembly operates as a waveguide antenna. When the diodes are disabled between these metal surfaces, the surfaces are unconnected with one another for RF signals.
摘要:
In a method and device for monitoring the physiologically effective radio-frequency exposure in at least one specific volume region of an examination subject in a magnetic resonance data acquisition scan in a magnetic resonance system, amplitude values are acquired that respectively represent, at specific acquisition points in time, a signal amplitude of the radio-frequency signals emitted or to be emitted via the radio-frequency signal channels. Also, phase values are acquired that represent the phases of the appertaining radio-frequency signals at these points in time. Local exposure values are then determined on the basis of the amplitude values and phase values, respectively representing a physiological exposure that the radio-frequency pulses cause at the examination subject at a specific location at a specific time. Based on this, exposure control values are determined that are compared with predetermined exposure limit values. When an exposure limit values is reached or exceeded, a control signal is output.
摘要:
In a method and device for monitoring the physiologically effective radio-frequency exposure in at least one specific volume region of an examination subject in a magnetic resonance data acquisition scan in a magnetic resonance system, the magnetic resonance system having a radio-frequency antenna structure with a number of individually controllable radio-frequency signal channels for generation of radio-frequency field distributions in an examination volume including the examination subject, amplitude values are acquired that respectively represent, at specific acquisition points in time, a signal amplitude of the radio-frequency signals emitted or to be emitted via the radio-frequency signal channels in the course of the magnetic resonance measurement. Also, phase values are acquired that represent the phases of the appertaining radio-frequency signals at these points in time. Local exposure values are then determined on the basis of the amplitude values and phase values, these local exposure values respectively representing a physiological exposure that the radio-frequency pulses cause at the examination subject at a specific location at a specific time. Based on this, exposure control values are determined that are compared with predetermined exposure limit values. When an exposure limit values is reached or exceeded, a control signal is output.
摘要:
In a method for correcting artifacts in magnetic resonance images that are caused, in a magnetic resonance device, by transverse magnetic field components that are oriented transverse to a basic magnetic field of the magnetic resonance device, wherein the magnetic resonance device has a gradient coil system for generating magnetic gradient fields and a high frequency transmitter for exciting magnetic resonance signals, during a measurement sequence a frequency correction value is fed to the high frequency transmitter for a correction area, this frequency correction value being determined dependent on the transverse magnetic field components, and/or an additional gradient field is produced for compensating the transverse magnetic field components.