A Novel Protection Device for Shock Wave Lithotripter

DESCRIPTION (provided by applicant): The shock wave lithotripsy (SWL) was first introduced successfully in clinical treatment in the earlier 1980s by Dornier Medical System in Germany. Now it has become the modality for urolithiasis diseases. However, SWL also causes acute renal injury, such as hemorrhage, hematoma, edema and enlargement of kidney. Although most patients recover well following treatment, there are subgroups of patients who are at much higher risk for chronic injury. These include patients with solitary kidneys, preexisting hypertension and, in particular, pediatric and elderly patients. Now none of the currently commercial lithotripters has been instrumented with any protection device for patient's safety in lithotripsy. The objective of this proposal is to commercialize a novel technology into a developed product for significant reduction of shock wave induced tissue injury without compromising stone comminution ability. Specifically, our aims are 1) to develop an innovative technique to reduce the contribution of edge wave to bubble cavitation, 2) to develop a prototype protection device based on the novel in situ edge wave suppression technique, 3) to evaluate the performance of the protection device in terms of the propensity of renal rupture and stone comminution, 4) to test the feasibility of diverse methods on modifying edge wave in lithotripter field, such as waveform inverting, blocking and scattering etc., and 5) to optimize the design and usage of protection device. A comprehensive physical characterization of the complete lithotripter system will be carried out, including acoustic field mapping, assessment of cavitation activities, high-speed imaging on bubble cavitation and phantom studies of stone fragmentation and vessel rupture. Standard quality assurance test, stability of suppression effect on shock wave induced bubble cavitation, consistency in stone fragments, will also be performed. This study would generate worldwide impact and significant benefit to the clinical management of patients suffering urolithiasis and the lithotripter manufacturers.