Title :
Nonlinear response of Sonazoid. Numerical simulations of pulse-inversion and subharmonics
Author_Institution :
Dept. of Telecommun., Norwegian Univ. of Sci. & Technol., Trondheim, Norway
Abstract :
The oscillation of Sonazoid contrast agent bubbles has been simulated numerically, using a modified Rayleigh-Plesset model including the effect of a shell. Pulse-inversion simulations showed how the echoes changed from inverted to time-shifted versions of each other as the driving amplitude increased. Simulations of subharmonic oscillations showed that the subharmonic mode was only present for some diameter-frequency combinations, and only above an amplitude threshold. This threshold was about 500 kPa, which is higher than values published for bubbles without a shell. For large bubbles, a chaotic oscillation pattern was found. A subharmonic mode was not always achieved for a finite-length pulse, even if it was predicted by CW results
Keywords :
biomedical ultrasonics; bubbles; chaos; damping; fluid oscillations; haemorheology; harmonic generation; nonlinear acoustics; Sonazoid contrast agent bubbles; amplitude threshold; bubble oscillation; chaotic oscillation pattern; driving amplitude dependence; modified Rayleigh-Plesset model; nonlinear contrast agent imaging; nonlinear response; numerical simulation; pulse-inversion; radiation damping; shell effect; subharmonic oscillations; time-shifted response; viscoelastic model; Acoustic imaging; Acoustic pulses; Chaos; Frequency; Mathematical model; Numerical simulation; Pulse inverters; Scattering; Ultrasonic imaging; Viscosity;
Conference_Titel :
Ultrasonics Symposium, 2000 IEEE
Conference_Location :
San Juan
Print_ISBN :
0-7803-6365-5
DOI :
10.1109/ULTSYM.2000.921692
