Patent ID: 7560931

Claim:
A switching apparatus configured to switch a state of an RF coil of a magnetic resonance imaging apparatus between a state in which a resonant circuit with a predetermined operating frequency as a resonant frequency is configured, and a state in which one of the resonant circuit and a non-resonant circuit having another resonant frequency is configured, said switching apparatus comprising: a coaxial cable having a length equal to an odd multiple of ¼of a wavelength corresponding to the operating frequency, said coaxial cable comprising: a first end at which an inner conductor is connected to a first side of a coil electrostatic capacitive element contained in the RF coil and an outer conductor is connected to a second side of the coil electrostatic capacitive element; and a second end from which a bias is applied; a diode connected to said inner conductor and said outer conductor at said second end of said coaxial cable; a lumped constant element connected to said inner conductor and said outer conductor in parallel with said diode at said second end of said coaxial cable, said lumped constant element having a predetermined electrostatic capacitance; and a shield case comprising a non-magnetic material having conductivity, said shield case covering said lumped constant element and positioned external to a coil shield body.