Method and device for detecting movement of a subject

A system for detecting movement of a subject located inside a magnetic resonance imaging device, the system comprising:

• an interface configured to receive at least one input signal;
• a multiplier and/or divider and/or a first mixer configured to use the at least one input signal to generate a higher pilot tone signal having a transmission frequency at least twice as high as a Larmor frequency of the magnetic resonance imaging device;
• a transmitting antenna configured to transmit the higher pilot tone signal;
• a receiving antenna configured to receive the transmitted higher pilot tone signal;
• a second mixer configured to use the at least one input signal to convert the transmission frequency of the transmitted higher pilot tone signal to an intermediate frequency equal to or lower than a frequency of the at least one input signal, thereby generating a transmitted pilot tone signal;
• and
• an interface configured to forward the transmitted pilot tone signal.

A local radio frequency (RF) coil for a magnetic resonance imaging device, the local RF coil configured to detect movement of a part of a body of a subject located in proximity thereto, the local RF coil comprising:

• at least one coil element configured to transmit a magnetic resonance signal;
• a coil connector configured to receive at least one input signal, wherein the at least one input signal comprises an oscillator signal and a pilot tone signal;
• and
• a system for detecting movement of a subject, wherein the system comprises:
• an interface configured to receive at least one input signal;
• a multiplier and/or divider and/or a first mixer configured to use the at least one input signal to generate a higher pilot tone signal having a transmission frequency at least twice as high as a Larmor frequency of the magnetic resonance imaging device;
• a transmitting antenna configured to transmit the higher pilot tone signal;
• a receiving antenna configured to receive the transmitted higher pilot tone signal;
• a second mixer configured to use the at least one input signal to convert the transmission frequency of the transmitted higher pilot tone signal to an intermediate frequency equal to or lower than a frequency of the at least one input signal, thereby generating a transmitted pilot tone signal;
• and
• an interface configured to forward the transmitted pilot tone signal.