DocumentCode :
915180
Title :
The role of inertial cavitation in acoustic droplet vaporization
Author :
Fabiilli, Mario L. ; Haworth, Kevin J. ; Fakhri, Nasir H. ; Kripfgans, Oliver D. ; Carson, Paul L. ; Fowlkes, J. Brian
Author_Institution :
Dept. of Radiol., Univ. of Michigan, Ann Arbor, MI
Volume :
56
Issue :
5
fYear :
2009
fDate :
5/1/2009 12:00:00 AM
Firstpage :
1006
Lastpage :
1017
Abstract :
The vaporization of a superheated droplet emulsion into gas bubbles using ultrasound-termed acoustic droplet vaporization (ADV)-has potential therapeutic applications in embolotherapy and drug delivery. The optimization of ADV for therapeutic applications can be enhanced by understanding the physical mechanisms underlying ADV, which are currently not clearly elucidated. Acoustic cavitation is one possible mechanism. This paper investigates the relationship between ADV and inertial cavitation (IC) thresholds (measured as peak rarefactional pressures) by studying parameters that are known to influence the IC threshold. These parameters include bulk fluid properties such as gas saturation, temperature, viscosity, and surface tension; droplet parameters such as degree of superheat, surfactant type, and size; and acoustic properties such as pulse repetition frequency and pulse width. In all cases the ADV threshold occurred at a lower rarefactional pressure than the IC threshold, indicating that the phase transition occurs before IC events. The viscosity and temperature of the bulk fluid are shown to influence both thresholds directly and inversely, respectively. An inverse trend is observed between threshold and diameter for droplets in the 1 to 2.5 mum range. Based on a choice of experimental parameters, it is possible to achieve ADV with or without IC.
Keywords :
biomedical ultrasonics; bubbles; cavitation; drops; drug delivery systems; emulsions; surface tension; surfactants; vaporisation; viscosity; acoustic droplet vaporization; droplet diameter; drug delivery applications; embolotherapy applications; fluid temperature; gas bubbles; gas saturation; inertial cavitation; pulse repetition frequency; pulse width; superheated droplet emulsion; surface tension; surfactant; therapeutic applications; viscosity; Acoustic applications; Acoustic measurements; Acoustic pulses; Drug delivery; Frequency; Space vector pulse width modulation; Surface tension; Temperature; Ultrasonic imaging; Viscosity; Data Interpretation, Statistical; Drug Delivery Systems; Embolization, Therapeutic; Emulsions; Fluorocarbons; Gases; Surface Properties; Temperature; Ultrasonics; Viscosity; Volatilization;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/TUFFC.2009.1132
Filename :
4976285
Link To Document :
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