RADIO FREQUENCY SAFETY SWITCH WITH ADJUSTABLE SWITCHING LEVEL FOR MRI SYSTEMS

摘要

A radio frequency antenna device (30) for use in a magnetic resonance imaging system (10), the magnetic resonance imaging system (10) being configured for acquiring magnetic resonance images of at least a portion of a subject of interest (20); the radio frequency antenna device (30) comprising—at least one radio frequency antennae (32) that is configured for being fed with radio frequency power from at least one radio frequency channel and for applying a radio frequency field B to nuclei of or within the portion of the subject of interest (20) for magnetic resonance excitation, —at least one pickup circuit (46), including an electric or electronic device having a non-linear current-voltage characteristic, —wherein the at least one pickup circuit (46) is configured to provide a trigger signal (56) upon a transfer of the electric or electronic device between a state of high impedance and a state of low impedance, the trigger signal (56) being exploitable for shutting down a supply of radio frequency power to the at least one radio frequency antenna (32) that is magnetically coupled to the at least one inductor (48); a method of operating a magnetic resonance imaging system (10) in a safe manner with regard to effects of emitted radio frequency power; and a method of operating a magnetic resonance imaging system (10) with regard to calibration of a magnitude of an emitted radio frequency magnetic field B1.