Circuit for active decoupling of transmit coils in nuclear magnetic resonance imaging apparatuses, particularly of the low field type

摘要

A circuit for active decoupling of transmit coils in Nuclear Magnetic Resonance imaging apparatuses, particularly of the low field type, including at least one PIN diode (D1), which is connected in series with the conductors of at least one transmit coil (1) and has at least one input (4) for an incoming bias current, there being provided means for generating and feeding such a bias current as to determine the conductive state of the PIN diode (D1), hence the operative state of the excitation pulse transmitting coil in synchronism with the start of excitation pulse transmission, and the nonconductive state of the PIN diode, i.e. the decoupling of the transmit coil from the receiving coil at the end of excitation pulse transmission. According to the invention, said circuit has at least one additional diode (D2) which is a silicon diode connected in antiparallel with the PIN diode (D1).