The dynamic behaviour of SonoVue microbubbles a new generation ultrasound contrast agent is investigated in real time with light scattering method.Highly diluted SonoVue microbubbles are injected into a diluted gel made of xanthan gum and water.The responses of individual SonoVue bubbles to driven ultrasound pulses are measured.Both linear and nonlinear bubble oscillations are observed and the results suggest that SonoVue microbubbles can generate strong nonlinear responses.By fitting the experimental data of individual bubble responses with Sarkars model,the shell coating parameter of the bubbles and dilatational viscosity is estimated to be 7.0 nm·s·Pa.