IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control ; DOI:10.1109/TUFFC.2011.1931
This study tests a deep-seated implantable ultrasonic pulser-receiver, powered wirelessly by magnetic coupling. A 30-cm energy-transmitting coil was designed to wrap around the body, and was driven by a current of 1.2 A rms at a frequency of 5.7 MHz to generate a magnetic field. A 2-cm receiving coil was positioned at the center of the primary coil for receiving the magnetic energy and powering the implantable device. A capacitor-diode voltage multiplier in the implantable circuit was used to step-up the receiving coil voltage from 12.5 to 50 V to operate an ultrasonic pulser. FEA magnetic field simulations, bench-top, and ex vivo rabbit measurements showed that the magnetic energy absorption in body tissue is negligible and that the magnetic coupling is not sensitive to receiving coil placement. The receiving coil and the power conditioning circuits in the implantable device do not contain ferromagnetic material, so a magnetic-resonance-compatible device can be achieved. A 5-MHz ultrasound transducer was used to test the implantable circuit, operating in pulse-echo mode. The received echo was amplified, envelope-detected, frequency-modulated, and transmitted out of the rabbit body by a radio wave. The modulated echo envelope signal was received by an external receiver located about 10 cm away from the primary coil. The study concludes that operation of a batteryless and wireless deep-seated implantable ultrasonic pulser-receiver powered by coplanar magnetic coupling is feasible.
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Clinic Ultrasound Laboratory (クレメント超音波研究室)
Cleveland Clinic (クリーブランド・クリニック),
Lerner Research Institute
Case Western Reserve University
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For a comprehensive listing see PUBLICATIONS
Clement GT, Nomura H, Adachi H, Kamakura T, Feasibility of non-contact ultrasound for medical imaging, Physics in Medicine and Biology 2014; 58: 6263-6278
Tang SC, Jolesz FA, Clement GT. A Wireless Batteryless Implantable Ultrasonic Pulser-Receiver. IEEE Trans Ultrason Ferroelectr Freq Control 2011;58:1211-21.
Paltiel HJ, Padua HM, Gargollo PC, Cannon GM Jr, Alomari AI, Yu R, Clement GT. Volumetric ultrasound imaging of tissue perfusion: preliminary results in a rabbit model... Phys Med Biol 2011;56:2183-97.
McDannold N, Clement GT, Black P, Jolesz F, Hynynen K. Focused ultrasound surgery of brain tumors: Initial findings in three patients. Neurosurgery 2010;66:323-32; discussion 332.
Clement GT, Hynynen K. A non-invasive method for focusing ultrasound through the human skull. Phys Med Biol 2002;47(8):1219-36.