A comparative study of systems used for dynamic focusing of ultrasound
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A comparative study of two methods used for dynamic focusing of ultrasound: the conventional phased arrays and a new method based on time reversal of acoustic signals is carried out. A laboratory model of the focusing system based on time reversal is developed and manufactured. One of the principal elements of the system is a reverberator with several piezoelectric transducers attached to its walls. Experiments are carried out to demonstrate the ability of such a system to generate one focus or several foci and to steer them electronically at considerable distances (50 mm at minimum) off the axis of the focusing system without causing the appearance of any grating lobes or other secondary intensity maxima. The focusing properties of the system are compared with the results of numerical simulation of two-dimensional phased arrays, whose parameters are taken to be typical for the arrays used in extracorporeal surgery. The important role of randomization is demonstrated for both of the aforementioned focusing methods. The prospects of practical application of the two methods are discussed.
PACS numbers43.60.Tj 43.80.Sh
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- 8.W. L. Nyborg, Physical Mechanisms for Biological Effects of Ultrasound, DHEW 78-8062 (US Government Printing Office, Washington, DC, 1977).Google Scholar
- 9.M. I. Skolnik, Introduction to Radar Systems, 2nd ed. (McGraw-Hill, New York, 1980).Google Scholar
- 11.J. W. Hand and L. R. Gavrilov, Great Britain Patent No. GB2347043.Google Scholar
- 12.J. W. Hand and L. R. Gavrilov, US Patent No. 6488630.Google Scholar
- 15.L. R. Gavrilov and J. Hand, Akust. Zh. 46, 456 (2000) [Acoust. Phys. 46, 390 (2000)].Google Scholar
- 16.L. R. Gavrilov, Akust. Zh. 49, 604 (2003) [Acoust. Phys. 49, 508 (2003)].Google Scholar
- 19.M. Fink, Sci. Amer., p. 91 (Nov., 1999).Google Scholar
- 23.A. Sutin and A. Sarvazyan, in Proc. World Congress on Ultrasonics, Paris, France, 2003, p. 1019.Google Scholar
- 24.B. K. Choi, A. Sutin, and A. Sarvazyan, Proc. of the 2006 IEEE International Ultrasonics Symposium, Vancouver, Canada, 2006, p. 2177.Google Scholar