Optimization of lithotripter waveform to reduce tissue injury without compromising stone comminution

To reduce the potential of vascular injury without compromising stone comminution in shock wave lithotripsy, an in situ pulse superposition technique has been developed to suppress intraluminal bubble expansion by modifying an HM-3 reflector based on theoretical analysis and pressure waveform measurement. Using high-speed imaging, it was found that the large Intraluminal bubble expansion was significantly suppressed using the upgraded reflector. Consequently, no rupture of vessel phantom could be observed near the lithotripter focus even after 200 shocks at 24 kV. In comparison, the vessel phantom could be ruptured within 50 shock using the original HM-3 reflector at 20 kV. At corresponding reflector configurations, stone phantom comminution is comparable up to 2,000 shocks. Furthermore, animal studies have demonstrated a significant reduction in renal injury using the upgraded reflector, which confirms the validity of this approach in vivo.