Abstract
When finite amplitude ultrasound propagation is considered, changes in spatial features of focused ultrasound beams can be observed. These nonlinear effects typically appears in thermoviscous fluids as focal displacements, beam-width variations or gain changes. However, in soft-tissue media, the frequency dependence of the attenuation doesn’t obeys a squared law. In this way, these complex media response leads to weak dispersion that prevents the cumulative processes of energy transfer to higher harmonics. In this work we explore the influence of different frequency power law attenuation responses and its influence on the self-defocusing effects in focused ultrasound beams. Thus, we numerically explore the spatial field distributions produced by low-Fresnel number devices and High Intensity Focused Ultrasound (HIFU) radiating trough different soft-tissue media.
BibTeX citation
@inproceedings{Jimenez2014a,
author = {Noé Jiménez and Javier Redondo and Víctor Sánchez-Morcillo and Pablo C. Iglesias and Francisco Camarena},
booktitle = {UIA 2014: 43rd Annual UIA Symposium. Madrid, Spain. 23 - 25 April},
doi = {https://doi.org/10.1016/j.phpro.2015.03.008},
editor = {Physics Procedia},
month = {4},
organization = {Ultrasonic Industry Association},
pages = {47-53},
publisher = {Elsevier},
series = {Oral},
title = {On the Nonlinear Effects in Focused Ultrasound Beams with Frequency Power Law Attenuation},
url = {https://www.sciencedirect.com/science/article/pii/S1875389215000796},
volume = {63},
year = {2014}
}