Effect of lithotripter focal width on stone comminution in shock wave lithotripsy.

Journal Article

Using a reflector insert, the original HM-3 lithotripter field at 20 kV was altered significantly with the peak positive pressure (p(+)) in the focal plane increased from 49 to 87 MPa while the -6 dB focal width decreased concomitantly from 11 to 4 mm. Using the original reflector, p(+) of 33 MPa with a -6 dB focal width of 18 mm were measured in a pre-focal plane 15-mm proximal to the lithotripter focus. However, the acoustic pulse energy delivered to a 28-mm diameter area around the lithotripter axis was comparable ( approximately 120 mJ). For all three exposure conditions, similar stone comminution ( approximately 70%) was produced in a mesh holder of 15 mm after 250 shocks. In contrast, stone comminution produced by the modified reflector either in a 15-mm finger cot (45%) or in a 30-mm membrane holder (14%) was significantly reduced from the corresponding values (56% and 26%) produced by the original reflector (no statistically significant differences were observed between the focal and pre-focal planes). These observations suggest that a low-pressure/broad focal width lithotripter field will produce better stone comminution than its counterpart with high-pressure/narrow focal width under clinically relevant in vitro comminution conditions.

Full Text

Duke Authors

Cited Authors

  • Qin, J; Simmons, WN; Sankin, G; Zhong, P

Published Date

  • April 2010

Published In

Volume / Issue

  • 127 / 4

Start / End Page

  • 2635 - 2645

PubMed ID

  • 20370044

Electronic International Standard Serial Number (EISSN)

  • 1520-8524

Digital Object Identifier (DOI)

  • 10.1121/1.3308409

Language

  • eng

Conference Location

  • United States