Journal of Ultrasound in Medicine 2005;24(8):1117-1125. PMID: 16040827
Objective. Advances in ultrasound transducer array and amplifier technologies have prompted many intriguing scientific proposals for ultrasound therapy. These include both mildly invasive and noninvasive techniques to be used in ultrasound brain surgery through the skull. In previous work, it was shown how a 500-element hemisphere-shaped transducer could correct the wave distortion caused by the skull with a transducer that operates at a frequency near 0.8 MHz. Because the objective for trans-skull focusing is its ultimate use in a clinical context, a new hemispheric phased-array system has now been developed with acoustic parameters that are optimized to match the values determined in preliminary studies. Methods. The transducer was tested by focusing ultrasound through ex vivo human skulls and into a brain phantom by means of a phase-adaptive focusing technique. Simultaneously, the procedure was monitored by the use of magnetic resonance guidance and thermometry. Results. The ultrasound focus of a 500-element 30-cm-diameter, 0.81-MHz array could be steered electronically through the skull over a volume of approximately 30 × 30 × 26 mm. Furthermore, temperature monitoring of the inner and outer surfaces of the skull showed that the array could coagulate targeted brain tissue without causing excessive skull heating. Conclusions. The successful outcome of these experiments indicates that intensities high enough to destroy brain tissue can be produced without excessive heating of the surrounding areas and without producing large magnetic resonance noise and artifacts.
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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
© 2013
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Clement GT, Nomura H, Adachi H, Kamakura T, Feasibility of non-contact ultrasound for medical imaging, Physics in Medicine and Biology 2013; 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.