Numerical analysis of bubble dynamics in electrohydraulic and electromagnetic shock wave lithotripsy

This study numerically investigated the bubble dynamics in electrohydraulic (EH) and electromagnetic (EM) shock wave lithotripsy (SWL). Methodology of acoustic pressure measurement was discussed to compare the performance of typical EH and EM lithotripters. The dynamics of cavitation bubbles in SWL has been numerically simulated using the Gilmore formulation coupled with zero-order gas diffusion. The illustrated pressure measurement results showed that both the peak positive and negative pressure of the Modularis at E4.0 are slightly higher than the corresponding values of the HM-3 at 20 kV. However, the pressure waveforms generated by an EH lithotripter is different from those of an EM lithotripter. The EM shock wave has a remarkable 2nd compressive pulse, which might suppress the cavitation activities in the EM lithotripter. In addition, the numerical simulation showed the EH lithotripter could produce stronger cavitation activities than the EM lithotripter.