Nuclear magnetic resonance imaging system with noise reduced intercom

摘要

A nuclear magnetic resonance imaging system with the intercom facility in which the disturbing and potentially harmful large noise due to the application of the reading gradient field pulses can be reduced at the exterior of the examination room. In the system, a connection between the microphone and the loudspeaker for transmitting the sounds generated inside the examination room to the exterior of the examination room is controlled according to the pulse sequence specified by the sequence controller such that the microphone and the loudspeaker are disconnected whenever the application of the reading gradient field pulse takes place. Alternatively, the system incorporates a notch filter connected between the microphone and the loudspeaker for transmitting the sounds generated inside the examination room to the exterior of the examination room, where the notch filter attenuates the component of the sounds having a central frequency equal to a repetition frequency of repeatedly applied reading gradient field pulses in the pulse sequence specified by the sequence controller.