Previous studies showed that ultrasound can mechanically remove tissue in a localized, controlled manner. Moreover, enhanced acoustic backscatter is highly correlated with the erosion process. “Initiation” and “extinction” of this highly backscattering environment were studied in this paper. The relationship between initiation and erosion, variability of initiation and extinction, and effects of pulse intensity and gas saturation on time to initiation (initiation delay time) were investigated. A 788-kHz single-element transducer was used. Multiple pulses at a 3-cycle pulse duration and a 20-kHz pulse repetition frequency were applied. values between 1000 and 9000 W/cm2 and gas saturation ranges of 24%–28%, 39%–49%, and 77%–81% were tested. Results show the following: (1) without initiation, erosion was never observed; (2) initiation and extinction of the highly backscattering environment were stochastic in nature and dependent on acoustic parameters; (3) initiation delay times were shorter with higher intensity and higher gas saturation (e.g., the mean initiation delay time was 66.9 s at of 4000 W/cm2 and 3.6 ms at of 9000 W/cm2); and (4) once initiated by high-intensity pulses, the highly backscattering environment and erosion can be sustained using a significantly lower intensity than that required to initiate the process.
REFERENCES
1.
AIUM (1998). Acoustic Output Measurement Standard for Diagnostic Ultrasound Equipment, AIUM/NEMA.
2.
Apfel
, R. E.
, and Holland
, C. K.
(1991
). “Gauging the likelihood of cavitation from short-pulse, low-duty cycle diagnostic ultrasound
,” Ultrasound Med. Biol.
17
, 179
–185
.3.
Atchley
, A. A.
(1988
). “Thresholds for cavitation produced in water by pulsed ultrasound
,” Ultrasonics
26
, xxx
–xxx
.4.
Belahadji
, B.
, Franc
, J. P.
, and Michel
, J. M.
(1991
). “A statistical analysis of cavitation erosion pits
,” J. Fluids Eng.
113
, 700
–706
.5.
Bouakaz
, A.
, Frinking
, P. J. A.
, Jong
, N. D.
, and Bom
, N.
(1999
). “Noninvasive measurement of the hydrostatic pressure in a fluid-filled cavity based on the disappearance time of micrometer-sized free gas bubbles
,” Ultrasound Med. Biol.
25
, 1407
–1415
.6.
Calabrese, A. M. (1996). Ph.D. thesis: “Threshold measurements and production rates for inertial cavitation due to pulsed, megahertz-frequency ultrasound,” Chaps. 5 and 6. The University of Mississippi.
7.
Chakravarty
, A.
, and Walton
, A. J.
(2001
). “Light emission from collapsing superheated steam bubbles in water
,” J. Lumin.
92
, 27
–33
.8.
Chen
, W. S.
, Matula
, T. J.
, and Crum
, L. A.
(2002
). “The disappearance of ultrasound contrast bubbles: Observations of bubble dissolution and cavitation nucleation
,” Ultrasound Med. Biol.
28
, 793
–803
.9.
Child
, S. Z.
, Hartman
, C. L.
, Schery
, L. A.
, and Carstensen
, E. L.
(1990
). “Lung damage from exposure to pulsed ultrasound
,” Ultrasound Med. Biol.
16
, 817
–825
.10.
Dalecki
, D.
, Raeman
, C. H.
, Child
, S. Z.
, and Carstensen
, E. L.
(1995
). “Intestinal hemorrhage from exposure to pulsed ultrasound
,” Ultrasound Med. Biol.
21
, 1067
–1072
.11.
Dunn
, F.
, and Fry
, F. J.
(1971
). “Ultrasonic threshold dosages for the mammalian central nervous system
,” IEEE Trans. Biomed. Eng.
18
, 253
–256
.12.
Everbach
, E. C.
, Makin
, I.
, Azadniv
, M.
, and Meltzer
, R. S.
(1997
). “Correlation of ultrasound-induced hemolysis with cavitation detector output in vitro
,” Ultrasound Med. Biol.
23
, 619
–624
.13.
Fairbank
, W. M.
, and Scully
, M. O.
(1977
). “A new non-invasive technique for cardiac pressure measurement resonant scattering of ultrasound from bubble
,” IEEE Trans. Biomed. Eng.
BME-24
, 107
–110
.14.
Frizzell
, L. A.
, Chen
, E.
, and Lee
, C.
(1994
). “Effects of pulsed ultrasound on the mouse neonate: Hind limb paralysis and lung hemorrhage [Comment]
,” Ultrasound Med. Biol.
20
, 53
–63
.15.
Fry
, F. J.
, Sanghvi
, N. T.
, Foster
, R. S.
, Bihrle
, R.
, and Hennige
, C.
(1995
). “Ultrasound and microbubbles: Their generation, detection, and potential utilization in tissue and organ therapy—experimental
,” Ultrasound Med. Biol.
21
, 1227
–1237
.16.
Holland
, C. K.
, and Apfel
, R. E.
(1990
). “Thresholds for transient cavitation produced by pulsed ultrasound in a controlled nuclei environment
,” J. Acoust. Soc. Am.
88
, 2059
–2069
.17.
Jarman
, P. D.
, and Taylor
, K. J.
(1965
). “Light flashes and shocks from a cavitation flow
,” Br. J. Appl. Phys.
16
, 675
–682
.18.
Jochle
, K.
, Debus
, J.
, Lorenz
, W. J.
, and Huber
, P.
(1996
). “A new method of quantitative cavitation assessment in the field of a lithotripter
,” Ultrasound Med. Biol.
22
, 329
–338
.19.
Kripfgans
, O. D.
, Fowlkes
, J. B.
, Miller
, D. L.
, Eldevik
, O. P.
, and Carson
, P. L.
(2000
). “Acoustic droplet vaporization for therapeutic and diagnostic applications
,” Ultrasound Med. Biol.
26
, 1177
–1189
.20.
Leighton, T. G. (1994). The Acoustic Bubble (Academic, London).
21.
Lush
, P. A.
, and Angell
, B.
(1984
). “Correlation of cavitation erosion and sound pressure level
,” J. Fluids Eng.
106
, 347
–351
.22.
Madanshetty
, S. I.
, Roy
, R. A.
, and Apfel
, R. E.
(1991
). “Acoustic microcavitation: Its active and passive acoustic detection
,” J. Acoust. Soc. Am.
90
, 1515
–1526
.23.
Matsumoto, Y., Yoshizawa, S., and Teiichiro, I. (2002). “Dynamics of bubble cloud in focused ultrasound,” International Symposium on Therapeutic Ultrasound, Seattle, WA, pp. 290–299.
24.
Messino
, C. D.
, Sette
, D.
, and Wanderlingh
, F.
(1963
). “Statistical approach to ultrasonic cavitation
,” J. Acoust. Soc. Am.
35
, 1575
–1583
.25.
Ohl
, C. D.
(2000
). “Luminescence from acoustic-driven laser-induced cavitation bubbles
,” Phys. Rev. E
61
, 1497
–1500
.26.
Ohl
, C. D.
, Lindau
, O.
, and Lauterborn
, W.
(1998
). “Luminescence from spherically and aspherically collapsing laser induced bubbles
,” Phys. Rev. Lett.
80
, 393
–396
.27.
Phillip
, A.
, and Lauterborn
, W.
(1998
). “Cavitation erosion by single laser-produced bubbles
,” J. Fluid Mech.
361
, 75
–116
.28.
Phillip, A., and Ohl, C. D. (1995). “Single bubble erosion on a solid surface,” Interational Symposium on Cavitation, CAV’95, Deuville, France, 297–303.
29.
Poliachik
, S. L.
(1999
). “Effect of high-intensity focused ultrasound on whole blood with and without microbubble contrast agent
,” Ultrasound Med. Biol.
25
, 991
–998
.30.
Roy, R. A., Church, C. C., and Calabrese, A. (1990a). “Cavitation produced by short pulses of ultrasound,” in Frontiers of Nonlinear Acoustics, 12 ISNA, edited by D. T. Blackstock and M. F. Hamilton (Elsevier, Amsterdam), pp. 476–491.
31.
Roy
, R. A.
, Madanshetty
, S. I.
, and Apfel
, R. E.
(1990b
). “An acoustic backscattering technique for the detection of transient cavitation produced by microsecond pulses of ultrasound
,” J. Acoust. Soc. Am.
87
, 2451
–2458
.32.
Roy
, R. A.
, Atchley
, A. A.
, Crum
, L. A.
, Fowlkes
, J. B.
, and Reidy
, J. J.
(1985
). “A precise technique for the measurement of acoustic cavitation thresholds and some preliminary results
,” J. Acoust. Soc. Am.
78
, 1799
–1805
.33.
Shi
, W. T.
, Forsberg
, F.
, Tornes
, A.
, Ostensen
, J.
, and Goldberg
, B. B.
(2000
). “Destruction of contrast microbubbles and the association with inertial cavitation
,” Ultrasound Med. Biol.
26
, 1009
–1019
.34.
Smith
, N. B.
, and Hynynen
, K.
(1998
). “The feasibility of using focused ultrasound for transmyocardial revascularization
,” Ultrasound Med. Biol.
24
, 1045
–1054
.35.
Tomlinson
, W. J.
, and Matthews
, S. J.
(1994
). “Cavitation erosion of aluminium alloys
,” J. Mater. Sci.
29
, 1101
–1108
.36.
Tran, B. C. (2003). “In Vivo Comparison of Multiple Pulse and CW strategies for Microbubble-Enhanced Ultrasound Therapy,” IEEE Ultrasonics Symposium, Hawaii, pp. 1J–4.
37.
Wetheril, G. B., and Brown, D. W. (1991). Statistical Process Control Theory and Practice (Chapman and Hall, London).
38.
Xu
, Z.
(2004
). “Controlled ultrasound tissue erosion
,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control
51
, 726
–736
.
This content is only available via PDF.
© 2005 Acoustical Society of America.
2005
Acoustical Society of America
You do not currently have access to this content.
