MRI apparatus and RF amplifier
AssigneeCanon Kabushiki Kaisha
InventorHisanori Suzuki
Life of this patent
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Abstract
In one embodiment, an MRI apparatus comprising: an RF coil configured to transmit an RF signal to an object; an RF amplifier configured to output the RF signal to a load including at least the RF coil and the object, wherein the RF amplifier comprises: an RF amplification circuit configured to amplify an inputted RF signal; and control circuitry configured to acquire load impedance information of the load in a first scan, determine compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
Claims15
An MRI apparatus, comprising:
- an RF coil configured to transmit an RF signal to an object;
- and
- an RF amplifier configured to output the RF signal to a load including at least the RF coil and the object, wherein the RF amplifier comprises:
- an RF amplification circuit configured to amplify an inputted RF signal;
- a memory that stores a plurality of nonlinearity compensation tables corresponding to a plurality of load impedances;
- and
- control circuitry configured to
- acquire load impedance information of the load in a first scan,
- select a nonlinearity compensation table for compensating an amplitude and a phase of the inputted RF signal for each amplitude from the plurality of nonlinearity compensation tables based on the load impedance information, wherein the plurality of nonlinearity compensation tables include a reference nonlinearity compensation table for compensating a predetermined reference load impedance,
- determine the selected nonlinearity compensation table as compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and
- compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
An MRI apparatus comprising:
- an RF coil configured to transmit an RF signal to an object;
- and an RF amplifier, wherein the RF amplifier comprises:
- an RF amplification circuit having a power amplification element that amplifies an inputted RF signal;
- and
- control circuitry configured to
- acquire imaging conditions having been set in a scan of imaging the object, the imaging conditions including at least a pulse width, a duty cycle, and an average power value,
- determine compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal depending on the imaging conditions, and
- compensate for the RF signal to be outputted from the RF amplification circuit in the scan for each amplitude of the inputted RF signal by using the compensation data.
An RF amplifier that amplifies an inputted RF signal and outputs an amplified RF signal to a load including at least an object and an RF coil configured to transmit the amplified RF signal to the object in an MRI apparatus, the RF amplifier comprising:
- an RF amplification circuit configured to amplify the inputted RF signal;
- a memory that stores a plurality of nonlinearity compensation tables corresponding to a plurality of load impedances;
- and
- control circuitry configured to
- acquire load impedance information of the load in a first scan,
- select a nonlinearity compensation table for compensating an amplitude and a phase of the inputted RF signal for each amplitude from the plurality of nonlinearity compensation tables based on the load impedance information, wherein the plurality of nonlinearity compensation tables include a reference nonlinearity compensation table for compensating a predetermined reference load impedance,
- determine the selected nonlinearity compensation table as compensation data for compensating nonlinearity of the RF signal to be outputted from the RF amplification circuit for each amplitude of the inputted RF signal based on the load impedance information, and
- compensate for the RF signal to be outputted from the RF amplification circuit in a second scan for each amplitude of the inputted RF signal by using the compensation data.
Dependencies are inferred from the claim text.