@inproceedings{161ec9e991174148b6e4dcc43ef9a1e8,
title = "Nonlinear modeling of pulsed and CW HIFU beams for dual-mode ultrasound arrays",
abstract = "Nonlinear propagation can have beneficial or detrimental effects on focused ultrasound beams for imaging and therapy. The advent of piezocomposite transducer technology have allowed for the fabrication of new generation of therapeutic arrays with relatively wide bandwidth and low cross coupling between elements (resulting in new dual-mode ultrasound array (DMUA) systems for imaging and therapy). The feedback capabilities of DMUAs offer new opportunities to characterize the HIFU beam in situ, including its spectral components due to harmonic generation. This form of feedback allows for the optimization of the DMUA driving patterns to achieve maximum therapeutic gain, by maximizing the harmonic generation within the focal spot. We present results of full 3D modeling of nonlinear wave propagation from the surface of currently available DMUA prototypes (1 and 3.5 MHz) into the treatment volume, modeled as heterogeneous absorbing medium. For example, a 1 MHz DMUA with f-number of 0.8 when geometrically focused at 100 mm with surface intensity of 2.2 W/cm2 was simulated. For 4-second exposure, accounting for harmonic generation resulted in ∼10% increase in peak temperature at the focus. We will present and discuss examples of complex DMUA focus patterns in the context of therapeutic gain.",
keywords = "Finite difference Timedomain, Modeling, Therapeutic Arrays, Thermal Dose, Tissue Ablation",
author = "Mohamed Almekkawy and Andrew Casper and John Ballard and Ebbini, {Emad S}",
year = "2012",
doi = "10.1063/1.4757301",
language = "English (US)",
isbn = "9780735410930",
series = "AIP Conference Proceedings",
pages = "3--8",
booktitle = "11th International Symposium on Therapeutic Ultrasound",
note = "11th International Symposium on Therapeutic Ultrasound, ISTU 2011 ; Conference date: 11-04-2011 Through 13-04-2011",
}