Back to results
US 6,320,385 B1Granted
Multi-channel balun for magnetic resonance apparatus
AssigneePicker International, Inc.
InventorsMichael Burl, Thomas Chmielewski, William O. Braum
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneePicker International, Inc.
InventorsMichael Burl, Thomas Chmielewski, William O. Braum
Estimating the term…
A multi-channel balun (70, 72) blocks stray RF current from flowing on shield conductors of coaxial RF cables of a magnetic resonance apparatus. The balun comprises a parallel combination of an even number of helical coils of shielded transmission cable (L10, L12; L14, L16, L18, L20) wound in alternate directions such that voltages iduced by their external RF fields cancel. One capacitor (C10; C16, C18) is connected in parallel symmetrically with each pair of helical coils, with trim capacitors (C12; C22) fixed in the coil plug (86, 90) to retune the balun as required. The multi-channel balun (70, 72) accommodates magnetic resonance systems with an odd or even number of channels without requiring shielding. Preferably, the balun (70, 72) is constructed on a single circuit board in a close-packed relationship that is compact and space efficient, yet provides better decoupling from the transmit field.
A magnetic resonance apparatus having a main magnet which generates a main magnetic field through an examination region, at least one RF coil assembly positioned adjacent the examination region, a radio frequency transmitter which drives the RF coil assembly to excite magnetic resonance dipoles in a RF transmit field within the examination region, a multi-channel receiver connected by shielded transmission cables to the at least one RF coil assembly which receives and demodulates the magnetic resonance signals, a multi-channel balun connected with the shielded transmission cables between the RF coil assembly and the multi-channel receiver to block stray induced RF currents and noise from entering the receiver, the multi-channel balun comprising:
A magnetic resonance apparatus having a main magnet which generates a main magnetic field through an examination region, at least one RF coil assembly positioned adjacent the examination region, a radio frequency transmitter which drives at least one RF coil of the at least one RF coil assembly to excite magnetic resonance dipoles in a RF transmit field within the examination region, a multichannel receiver connected by shielded transmission cables to a plurality of RF coils of the at least one RF coil assembly which receives and demodulates the magnetic resonance signals, a multi-channel balun connected with the shielded transmission cables between the RF coil assembly and the multi-channel receiver to block stray induced radio frequency currents and noise from entering the channels of the multichannel receiver, the multi-channel balun comprising:
A multi-channel balun for blocking stray RF current from flowing in RF lines, said multi-channel balun comprising:
A multi-channel balun for blocking stray RF currents from flowing in RF lines, said multi-channel balun comprising:
A method for blocking stray RF currents from flowing in signal cables carrying RF data of a selected frequency spectrum in a magnetic resonance apparatus, said method comprising:
Dependencies are inferred from the claim text.