Encapsulated contrast microbubble radial oscillation associated with postexcitation pressure peaks

Autor: Mathieu Santin, Josquin Foiret, Daniel A. King, William D. O'Brien, Alexander Haak, S. L. Bridal
Rok vydání: 2010
Předmět:
Zdroj: The Journal of the Acoustical Society of America. 127:1156-1164
ISSN: 0001-4966
DOI: 10.1121/1.3277216
Popis: This work combines modeling and experiment to assess encapsulated microbubble oscillations associated with broadband pressure peaks detected after microbubble excitation (postexcitation signals). Data were acquired from albumin-shelled and phospholipid-shelled microbubbles using a passive cavitation detector consisting of a confocally aligned 2.8-MHz transmitter and 13-MHz receiver. Microbubbles in weak solutions were insonified with a 5-cycle pulse at a peak rarefactional pressure of 2.0+/-0.2 MPa. For each microbubble type, at least 100 received signals were identified as individual-microbubble responses. The average broadband noise from signals with postexcitation response was 4.2-7.2 dB higher than from signals without postexcitation. Pressure-time responses for each microbubble type were simulated using the model by Marmottant et al. [J. Acoust. Soc. Am. 118, 3499-3505 (2005)], with insonification conditions matching the experiment. Increased broadband noise predicted for microbubbles with postexcitation response was consistent with that observed experimentally (4.0-8.9 dB). The model predicted that postexcitation signals occur only when the radial oscillation exceeds both the shell break-up threshold and twice the initial radius (free bubble inertial cavitation threshold).
Databáze: OpenAIRE