Document Type : Full Research Paper


1 M.Sc Graduated, Biomedical Engineering Group, School of Electrical Engineering, Iran University of Science and Technology

2 Assistant Professor, Biomedical Engineering Group, School of Electrical Engineering, Iran University of Science and Technology



Vibroacoustography is a relatively new elasticity imaging method that uses dynamic (oscillatory) radiation force of ultrasound to vibrate the tissue at low frequency (Kilo Hertz). The resulting acoustic emission is recorded with sensitive hydrophone to produce images that are related to the mechanical properties of the tissue. This force is produced by two continuous overlapping ultrasound beams that have a slightly different frequency. Vibroacoustography has been applied to image breast and arteries microcalcification. The lateral resolution of this imaging method is about 0.7mm and its axial resolution is about 12 mm. In this paper two major methods of producing dynamic radiation force, Confocal and X-focal (consists of two concave transducers whose axes cross at their foci at an angle q), are analyzed. A new method for improving axial resolution using short duration pulses is introduced. Simulation results show that we have about 50% improvement in axial resolution using short duration pulses.


Main Subjects

[1]     Fatemi M., Greenleaf J.F., Ultrasound stimulated vibro-acoustic spectroscope; Science, 1998; 280: 82– 85.
[2]     Fatemi M., Greenleaf J.F., Vibro-acoustography: An imaging modality based on ultrasound-stimulated acoustic emission; Proc. Natl. Acad. Sci. USA, 1999; 96: 6603-6608.
[3]     Fatemi M., Wold L.E., Alizad A., Greenleaf J.F., Vibro-acoustic tissue mammography; IEEE. Trans. Med. Imag., 2002; 21(1), 1-8.
[4]     Alizad A., Fatemi M., Nishimura R.A., Kinnick R.R., Rambod E., Greenleaf J.F., Detection of calcium deposits on heart valve leaftlets by vibroacoustography: An in vitro study; J. Amer. Soc. Echocardiogr, 2002; 15: 1291–1395.
[5]     Fatemi M., Rambod E., Gharib M., Greenleaf J.F., Nondestructive testing of mechanical heart valves by vibroacoustography, presented at 7th Int. Congr. Sound and Vibration, July 4–7, 2000.
[6]     Callé S., Remenieras J.P., Matar O.B., Defontaine M., Patat F., Application of nonlinear phenomena induced by focused ultrasound to bone imaging; Ultrasound Med. Biol., 2003; 29(3): 465–472.
[7]     Fatemi M. Greenleaf J.F., Probing the dynamics of tissue at low frequencies with the radiation force of ultrasound; Phys. Med. Biol., 2000; 45: 1449-1464.
[8]     Mitri F.G., Trompette P., Yves Chapelon J., Improving the Use of Vibro-Acoustography for Brachytherapy Metal Seed Imaging: A Feasibility Study; IEEE Trans. Med. Imag, 2004; 23(1): 1221-1230.
[9]     Westervelt P.J., The theory of steady forces caused by sound waves; J. Acoust. Soc. Amer., 1951; 23: 312- 315.
[10] Chen X., Schwarz K.Q., Parker K.J., Radiation pattern of a focused transducer: A numerically convergent solution; J. Acoust. Soc. Amer., 1993; 94: 2979–2991.
[11] Cobbold R.S., Foundation of biomedical ultrasound; Oxford university press, 2006: 3.16-3.49.
[12] Silva G.T., Image formation in vibroacoustography; A Thesis Submitted to the Faculty of the Mayo Graduate School, 2004.
[13] Silva G.T., Chen S., Greenleaf J.F., Fatemi M., Dynamic ultrasound radiation force in fluids; Phys. Rev. E, 2006; 71: 561 573.
[14] Chen S., Fatemi M., Kinnick R., Greenleaf J.F., Comparison of Stress Field Forming Methods for Vibro-acoustography; ieee transactions on ultrasonics, ferroelectrics, and frequency control, 2004; 51(3): 675- 682.
[15] Lee C.P., Wang T.G., Acoustic radiation pressure; Journal of the Acoustical Society of America, 1993; 94(2):1099–1109.
[16] Greenleaf J.F., Fatemi M., Insana M., Selected methods for imaging elastic properties of biological tissues; Annu. Rev. Biomed. Eng., March 2003.
[17] Chen S., Fatemi M., Greenleaf J.F., Radiation force induced vibration of a sphere in viscoelastic medium; J. Acoust. Soc. Amer. pt. 1, 2002; 112(3), 886–889.
[18] Walker C.L., Foster F.S., Plewes D.B., Magnetic resonance imaging of ultrasonic fields; Ultrasound Med. Biol, 1998; 24: 137–142.
[19] Urban M.W., Greenleaf J.F., Dynamic Signal Arrival Correction For Vibro-Acoustography; IEEE Trans. Med. Imag, 2006; 21(1): 986-997.