Measurement and analysis of vibrations on surface of phantom induced by piezoelectric extracorporeal shock wave lithotripter

We investigated the sound radiated from an object, induced by a piezoelectric extracorporeal shock wave lithotripter (ESWL). However, it was found that more direct measurement is necessary to analyze the sounds in piezoelectric ESWL. Therefore, we investigate the vibrations of a phantom, which are directly measured using laser Doppler velocimetry. The results show that the peak frequency in the power spectrum shifts as the number of shots increases from high frequency to low frequency. The previous results are confirmed by detecting the characteristic peaks obtained from the vibrations of bronze models. The bronze models are used to simulate the phantom during the breaking process. It is found that it is more difficult to make the models vibrate exactly at the focal point than above or below the focal region. These results will be applied to the monitoring of the breaking process and the choice of the optimum focal point on the calculus.