Physics in Medicine and Biology ; DOI:10.1088/0031-9155/57/4/901
This paper proposes the use of a k-space method to obtain the correction for transcranial ultrasound beam focusing. Mirroring past approaches, a synthetic point source at the focal point is numerically excited, and propagated through the skull, using acoustic properties acquired from registered computed tomography of the skull being studied. The received data outside the skull contain the correction information and can be phase conjugated (time reversed) and then physically generated to achieve a tight focusing inside the skull, by assuming quasi-plane transmission where shear waves are not present or their contribution can be neglected. Compared with the conventional finite-difference time-domain method for wave propagation simulation, it will be shown that the k-space method is significantly more accurate even for a relatively coarse spatial resolution, leading to a dramatically reduced computation time. Both numerical simulations and experiments conducted on an ex vivo human skull demonstrate that precise focusing can be realized using the k-space method with a spatial resolution as low as only 2.56 grid points per wavelength, thus allowing treatment planning computation on the order of minutes.
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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
© 2014
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.