title: Depletion-Mode GaN HEMT Q-Spoil Switches for MRI Coils.
abstract: Q-spoiling is the process of decoupling an MRI receive coil to protect the equipment and patient. Conventionally, Q-spoiling is performed using a PIN diode switch that draws significant current. In this work, a Q-spoiling technique using a depletion-mode Gallium Nitride HEMT device was developed for coil detuning at both 1.5 T and 3 T MRI. The circuits with conventional PIN diode Q-spoiling and the GaN HEMT device were implemented on surface coils. SNR was measured and compared for all surfaces coils. At both 1.5 T and 3 T, comparable SNR was achieved for all coils with the proposed technique and conventional Q-spoiling. The GaN HEMT device has significantly reduced the required power for Q-spoiling. The GaN HEMT device also provides useful safety features by detuning the coil when unpowered.
authors.forename: Jonathan Y
authors.initials: JY
authors.lastname: Lu
authors.forename: Thomas
authors.initials: T
authors.lastname: Grafendorfer
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Shreyas
authors.initials: S
authors.lastname: Vasanawala
authors.forename: Fraser
authors.initials: F
authors.lastname: Robb
authors.forename: John M
authors.initials: JM
authors.lastname: Pauly
authors.forename: Greig C
authors.initials: GC
authors.lastname: Scott
mesh_terms: D004867:Equipment Design; D005708:Gallium / Q000737:chemistry*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D059629:Signal-To-Noise Ratio
chemical_list: C473348:gallium nitride; D005708:Gallium