Models mimicking characteristics of the urinary system and stones relevant to lithotripsy

Both new and established modes of noninvasive lithotripsy are often tested in an in vitro apparatus to evaluate the efficacy of different technologies and exposures to fragment urinary stones. A significant challenge for these experiments is to accurately replicate the physical properties of a stone and the surrounding urinary tract. Such a task requires appropriate models for the stone, the fluid, and the tissue, all of which can contribute to stone fragmentation. This presentation will describe research into new models to more accurately replicate the fracture of natural human stones, including artificial models and natural stones from other mammalian species. Experiments show several factors such as fluid gas concentration, tissue phantom properties, and fluid confinement and also affect cavitation behavior and lithotripsy effectiveness. Experiments measuring such cavitation activity in vivo in a porcine model and correlation with in vitro observations will be presented. Altogether, these studies suggest that lithotripsy experiments are dependent on these characteristics and require careful choice of models to mimic in vivo scenarios. [Work supported by NIDDK K01 DK104854 and P01 DK043881.]