Magnetic resonance imaging system with a class-E radio frequency amplifier having a feedback circuit
AssigneeKenergy, Inc.
InventorsCherik Bulkes, Stephen Denker, Arthur J. Beutler
Life of this patent
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Abstract
A Class-E amplifier has been adapted for use in the radio frequency section that drives a transmit coil of a magnetic resonance imaging (MRI) system. The Class-E amplifier responds to a radio frequency carrier signal and a control signal by producing a radio frequency excitation signal for driving the transmit coil. The Class-E amplifier includes a pickup coil that senses a signal emitted from the transmit coil and produces a feedback signal that is used to alter the control signal and thereby control production of the radio frequency excitation signal.
Claims21
A radio frequency section for a magnetic resonance imaging system that transmits a radio frequency excitation signal into an object being imaged, the radio frequency section comprising:
- a transmit coil for placement around the object;
- a drive circuit which produces a radio frequency control signal;
- and
- a Class-E amplifier that in response to the radio frequency control signal produces the radio frequency excitation signal which is applied to the transmit coil, wherein the Class-E amplifier includes a sensor that detects the radio frequency excitation signal emitted from the transmit coil and produces a feedback signal which controls production of the radio frequency excitation signal.
A radio frequency section for a magnetic resonance imaging system that transmits a radio frequency excitation signal into an object being imaged, the radio frequency section comprising:
- a transmit coil having a plurality of rungs;
- an exciter which produces a radio frequency carrier signal;
- a distribution circuit that receives the radio frequency carrier signal and an envelope signal designating a desired intensity level for the radio frequency excitation signal and in response thereto produces a radio frequency control signal, the distribution circuit comprising a power splitter that divides the radio frequency control signal into a plurality of sub-drive signals, one of which for each rung of the transmit coil;
- and
- a first plurality of Class-E amplifiers, each one having a first pickup coil that produces a given first feedback signal indicating an intensity of a radio frequency signal emitted from the transmit coil, and each of the first plurality of Class-E amplifiers responding to one of the sub-drive signals and the given first feedback signal by producing a radio frequency excitation signal that is applied to one of the plurality of rungs of the transmit coil.
Dependencies are inferred from the claim text.