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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 4 Issue 2 (1998) pp 247-255
Response of bubbles to diagnostic ultrasound: a unifying theoretical approach
S. Hilgenfeldt (1) (a), D. Lohse (1) (b), M. Zomack (2)
(1) Fachbereich Physik der Universität Marburg, Renthof 6, 35032 Marburg, Germany
(2) Schering AG, Clinical Development, Müllerstr. 178, 13342 Berlin, Germany
Received: 26 February 1998 / Revised: 13 March 1998 / Accepted: 15 March 1998
Abstract: The scattering of ultrasound from bubbles of $\sim 1 \mu$m radius, such as used in contrast enhancers for ultrasound diagnostics, is studied. We show that sound scattering and "active" emission of sound from oscillating bubbles are not contradictory, but are just two different aspects derived from the same physics. Treating the bubble as a nonlinear oscillator, we arrive at general formulas for scattering and absorption cross-sections. We show that several well-known formulas are recovered in the linear limit of this ansatz. In the case of strongly nonlinear oscillations, however, the cross-sections can be larger than those for linear response by several orders of magnitude. The major part of the incident sound energy is then converted into emitted sound, unlike what happens in the linear case, where the absorption cross-sections exceed the scattering cross-sections.
PACS. 87.59.Mt Ultrasonography - 43.80.+p Bioacoustics - 43.25.+y Nonlinear acoustics, macrosonics
(a) Present address: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, MA 02138, USA; e-mail:sacha@stockes.harvard.edu
(b) Present address: University of Twente, Applied Physics, Postbus 217, 7500 AE Enschede, The Nederlands; email: lohse@utwente.nl
Article in PDF-Format (372 KB)
Online publication: August 10, 1998
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