Transient cavitation and acoustic emission produced by different laser lithotripters.

Published

Journal Article

Transient cavitation and shockwave generation produced by pulsed-dye and holmium:YAG laser lithotripters were studied using high-speed photography and acoustic emission measurements. In addition, stone phantoms were used to compare the fragmentation efficiency of various laser and electrohydraulic lithotripters. The pulsed-dye laser, with a wavelength (504 nm) strongly absorbed by most stone materials but not by water, and a short pulse duration of approximately 1 microsec, induces plasma formation on the surface of the target calculi. Subsequently, the rapid expansion of the plasma forms a cavitation bubble, which expands spherically to a maximum size and then collapses violently, leading to strong shockwave generation and microjet impingement, which comprises the primary mechanism for stone fragmentation with short-pulse lasers. In contrast, the holmium laser, with a wavelength (2100 nm) most strongly absorbed by water as well as by all stone materials and a long pulse duration of 250 to 350 microsec, produces an elongated, pear-shaped cavitation bubble at the tip of the optical fiber that forms a vapor channel to conduct the ensuing laser energy to the target stone (Moss effect). The expansion and subsequent collapse of the elongated bubble is asymmetric, resulting in weak shockwave generation and microjet impingement. Thus, stone fragmentation in holmium laser lithotripsy is caused primarily by thermal ablation (drilling effect).

Full Text

Duke Authors

Cited Authors

  • Zhong, P; Tong, HL; Cocks, FH; Pearle, MS; Preminger, GM

Published Date

  • August 1998

Published In

Volume / Issue

  • 12 / 4

Start / End Page

  • 371 - 378

PubMed ID

  • 9726407

Pubmed Central ID

  • 9726407

Electronic International Standard Serial Number (EISSN)

  • 1557-900X

International Standard Serial Number (ISSN)

  • 0892-7790

Digital Object Identifier (DOI)

  • 10.1089/end.1998.12.371

Language

  • eng