Jet formation and shock wave emission during collapse of ultrasound-induced cavitation bubbles and their role in the therapeutic applications of high-intensity focused ultrasound

The dynamics of inertial cavitation bubbles produced by short pulses of high-intensity focused ultrasound near a rigid boundary are studied to get a better understanding of the role of jet formation and shock wave emission during bubble collapse in the therapeutic applications of ultrasound. The bubble dynamics are investigated by high-speed photography with up to 2 million frames/s and acoustic measurements, as well as by numerical calculations. The significant parameter of this study is the dimensionless stand-off, gamma, which is defined as the distance of the bubble centre at its maximum expansion scaled by the maximum bubble radius. High-speed photography is applied to observe the bubble motion and the velocity of the liquid jet formed during bubble collapse. Hydrophone measurements are used to determine the pressure and the duration of the shock wave emitted during bubble rebound. Calculations yield the variation with time of the bubble wall, the maximum velocity and the kinetic energy of the re-entrant jet. The comparisons between experimental and numerical data are favourable with regard to both shape history and translational motion of the bubble. The acoustic energy constitutes the largest individual amount in the energy balance of bubble collapse. The ratio of the shock wave energy, measured at 10 mm from the emission centre, to the cavitation bubble energy was 1:2.4 at gamma = 1.55 and 1:3.5 at gamma = 1. At this distance, the shock wave pressure ranges from 0.122 MPa, at gamma = 1, to 0.162 MPa, at gamma = 1.55, and the temporal duration at the half maximum level is 87 ns. The maximum jet velocity ranges from 27 m s(-1), at gamma = 1, to 36 m s(-1), at gamma = 1.55. For gamma < 1.2, the re-entrant jet can generate an impact pressure on the nearby boundary larger than 50 MPa. We discuss the implications of the results for the therapeutic applications of high-intensity focused ultrasound.

[1]  Kenneth S. Suslick,et al.  The Chemical Effects of Ultrasound , 1989 .

[2]  E. Carstensen,et al.  Lung damage from exposure to pulsed ultrasound. , 1990, Ultrasound in medicine & biology.

[3]  Morton W. Miller,et al.  A review of in vitro bioeffects of inertial ultrasonic cavitation from a mechanistic perspective. , 1996, Ultrasound in medicine & biology.

[4]  C. Rotsch,et al.  Dimensional and mechanical dynamics of active and stable edges in motile fibroblasts investigated by using atomic force microscopy. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[5]  K Hynynen,et al.  The feasibility of using focused ultrasound for transmyocardial revascularization. , 1998, Ultrasound in medicine & biology.

[6]  J. Best.  The formation of toroidal bubbles upon the collapse of transient cavities , 1993, Journal of Fluid Mechanics.

[7]  G. Truskey,et al.  Atomic force and total internal reflection fluorescence microscopy for the study of force transmission in endothelial cells. , 2000, Biophysical journal.

[8]  Michael J. Miksis,et al.  Bubble Oscillations of Large Amplitude , 1980 .

[9]  Werner Lauterborn,et al.  Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary , 1989, Journal of Fluid Mechanics.

[10]  Samir Mitragotri,et al.  Interactions of inertial cavitation bubbles with stratum corneum lipid bilayers during low-frequency sonophoresis. , 2003, Biophysical journal.

[11]  H. Nagawa,et al.  Erythrocytes, as well as microbubble contrast agents, are important factors in improving thermal and therapeutic effects of high-intensity focused ultrasound. , 2005, Ultrasound in medicine & biology.

[12]  Timothy G. Leighton,et al.  Studies of the cavitational effects of clinical ultrasound by sonoluminescence: 3. Cavitation from pulses a few microseconds in length , 1989 .

[13]  G. S. Keen,et al.  The final stage of the collapse of a cavitation bubble close to a rigid boundary , 2002, Physics of Fluids.

[14]  Y. Matsumoto,et al.  Dynamics of ultrasound-induced cavitation bubbles in non-Newtonian liquids and near a rigid boundary , 2004 .

[15]  C. Brennen.  Cavitation and Bubble Dynamics , 1995 .

[16]  G. Vanderstraeten,et al.  Phonophoresis versus topical application of ketoprofen: comparison between tissue and plasma levels. , 2003, Physical therapy.

[17]  W. Kraus,et al.  Endothelial, cardiac muscle and skeletal muscle exhibit different viscous and elastic properties as determined by atomic force microscopy. , 2001, Journal of biomechanics.

[18]  Raffi Bekeredjian,et al.  Ultrasound-Targeted Microbubble Destruction Can Repeatedly Direct Highly Specific Plasmid Expression to the Heart , 2003, Circulation.

[19]  J. Brunton.  A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - High speed liquid impact , 1966, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[20]  T. Leighton.  The Acoustic Bubble , 1994 .

[21]  Y Lasne,et al.  Local control of prostate cancer by transrectal high intensity focused ultrasound therapy: preliminary results. , 1999, The Journal of urology.

[22]  D. Miller,et al.  The relationship of scattered subharmonic, 3.3-MHz fundamental and second harmonic signals to damage of monolayer cells by ultrasonically activated Albunex. , 1998, The Journal of the Acoustical Society of America.

[23]  Koichi Ogawa,et al.  Induction of cell-membrane porosity by ultrasound , 1999, The Lancet.

[24]  D. Dalecki,et al.  Ultrasonic excitation of a bubble near a rigid or deformable sphere: implications for ultrasonically induced hemolysis. , 2005, The Journal of the Acoustical Society of America.

[25]  Emil-Alexandru Brujan,et al.  The role of cavitation microjets in the therapeutic applications of ultrasound. , 2004, Ultrasound in medicine & biology.

[26]  S. Otto,et al.  Jets in bubbles , 2004 .

[27]  L A Crum,et al.  The significance of membrane changes in the safe and effective use of therapeutic and diagnostic ultrasound. , 1989, Physics in medicine and biology.

[28]  R. Leveillee,et al.  Intracorporeal lithotripsy: which modality is best? , 2003, Current opinion in urology.

[29]  C. Visser,et al.  Microbubbles and ultrasound: from diagnosis to therapy. , 2004, European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology.

[30]  M. Davies,et al.  Atherosclerotic plaque caps are locally weakened when macrophages density is increased. , 1991, Atherosclerosis.

[31]  F. Dunn,et al.  SELECTED NON-THERMAL MECHANISMS OF INTERACTION OF ULTRASOUND AND BIOLOGICAL MEDIA , 1978 .