[The Dornier lithotripter in a comparison. Measuring shockwave fields and fragmentation effects]

Area of Science:

• Biomedical Engineering
• Acoustics
• Medical Devices

Background:

• Extracorporeal shock wave lithotripsy (ESWL) is a key treatment for kidney stones.
• Accurate characterization of shock wave fields is crucial for optimizing lithotripter performance.
• Dornier lithotripters are widely used, necessitating detailed performance analysis.

Purpose of the Study:

• To perform comparative shock wave field measurements for Dornier lithotripters.
• To analyze the relationship between shock wave energy and stone fragmentation.
• To investigate factors influencing shock wave focusing and energy delivery.

Main Methods:

• Utilized a modern piezoelectric polyvinylidene fluoride (PVDF) shock wave measuring technique.
• Employed a high temporal and spatial resolution pressure probe for detailed field mapping.
• Conducted in vitro experiments comparing incident shock energies on model calculi with fragmentation results.

Main Results:

• Detailed shock wave field characteristics, including maximum amplitudes and pressure distributions, were mapped.
• Reflector geometry, diffraction, and non-linear propagation effects were identified as key influences on focusing.
• Stone fragmentation efficiency was found to be inversely proportional to the square of capacitor voltage and directly proportional to calculus volume.

Conclusions:

• The study provides precise data on Dornier lithotripter shock wave fields.
• Understanding focus energy is critical for predicting and improving stone disintegration.
• Capacitor voltage is a primary determinant of lithotripsy effectiveness, offering a target for treatment optimization.