TY - JOUR
T1 - Standalone RF Self-Interference Cancellation System for In-Vivo Simultaneous Transmit and Receive (STAR) MRI
AU - Colwell, Zachary A.
AU - Delabarre, Lance
AU - Idiyatullin, Djaudat
AU - Adriany, Gregor
AU - Garwood, Michael
AU - Vaughan, J. Thomas
AU - Sohn, Sung Min
N1 - Publisher Copyright:
© 2007-2012 IEEE.
PY - 2023/6/1
Y1 - 2023/6/1
N2 - Demonstrated is a standalone RF self-interference canceller for simultaneous transmit and receive (STAR) magnetic resonance imaging (MRI) at 1.5T. Standalone STAR cancels the leakage signal directly coupled between transmit and receive RF coils. A cancellation signal, introduced by tapping the input of a transmit coil with a power divider, is manipulated with voltage-controlled attenuators and phase shifters to match the leakage signal in amplitude, 180° out of phase, to exhibit high isolation between the transmitter and receiver. The cancellation signal is initially generated by a voltage-controlled oscillator (VCO); therefore, it does not require any external RF or synchronization signals from the MRI console for calibration. The system employs a field programmable gate array (FPGA) with an on-board analog to digital converter (ADC) to calibrate the cancellation signal by tapping the receive signal, which contains the leakage signal. Once calibrated, the VCO is disabled and the transmit signal path switches to the MRI console for STAR MR imaging. To compensate for the changes of parameters in RF sequences after the automatic calibration and to further improve isolation, a wireless user board that uses an ESP32 microcontroller was built to communicate with the FPGA for final fine-tuning of the output state. The standalone STAR system achieved 74.2 dB of isolation with a 94 second calibration time. With such high isolation, in-vivo MR images were obtained with approximately 40 mW of RF peak power.
AB - Demonstrated is a standalone RF self-interference canceller for simultaneous transmit and receive (STAR) magnetic resonance imaging (MRI) at 1.5T. Standalone STAR cancels the leakage signal directly coupled between transmit and receive RF coils. A cancellation signal, introduced by tapping the input of a transmit coil with a power divider, is manipulated with voltage-controlled attenuators and phase shifters to match the leakage signal in amplitude, 180° out of phase, to exhibit high isolation between the transmitter and receiver. The cancellation signal is initially generated by a voltage-controlled oscillator (VCO); therefore, it does not require any external RF or synchronization signals from the MRI console for calibration. The system employs a field programmable gate array (FPGA) with an on-board analog to digital converter (ADC) to calibrate the cancellation signal by tapping the receive signal, which contains the leakage signal. Once calibrated, the VCO is disabled and the transmit signal path switches to the MRI console for STAR MR imaging. To compensate for the changes of parameters in RF sequences after the automatic calibration and to further improve isolation, a wireless user board that uses an ESP32 microcontroller was built to communicate with the FPGA for final fine-tuning of the output state. The standalone STAR system achieved 74.2 dB of isolation with a 94 second calibration time. With such high isolation, in-vivo MR images were obtained with approximately 40 mW of RF peak power.
KW - Biomedical electronics
KW - full-duplex system
KW - interference cancellation
KW - magnetic resonance imaging
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U2 - 10.1109/TBCAS.2023.3275849
DO - 10.1109/TBCAS.2023.3275849
M3 - Article
C2 - 37171925
AN - SCOPUS:85159842169
SN - 1932-4545
VL - 17
SP - 610
EP - 620
JO - IEEE transactions on biomedical circuits and systems
JF - IEEE transactions on biomedical circuits and systems
IS - 3
ER -