Lu Jonathan Y, Grafendorfer Thomas, Zhang Tao, Vasanawala Shreyas, Robb Fraser, Pauly John M, Scott Greig C
IEEE Trans Med Imaging. 2016 Dec;35(12):2558-2567. doi: 10.1109/TMI.2016.2586053. Epub 2016 Jun 28.
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.
Q值破坏是使MRI接收线圈去耦以保护设备和患者的过程。传统上，Q值破坏是使用会消耗大量电流的PIN二极管开关来执行的。在这项工作中，开发了一种使用耗尽型氮化镓高电子迁移率晶体管（HEMT）器件的Q值破坏技术，用于1.5 T和3 T MRI的线圈失谐。采用传统PIN二极管Q值破坏的电路和氮化镓HEMT器件被应用于表面线圈。对所有表面线圈的信噪比进行了测量和比较。在1.5 T和3 T时，采用所提出的技术和传统Q值破坏方法的所有线圈都获得了相当的信噪比。氮化镓HEMT器件显著降低了Q值破坏所需的功率。氮化镓HEMT器件还通过在未通电时使线圈失谐提供了有用的安全特性。
