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Proceedings Paper

Laser mass-ablation efficiency measurements indicate bubble-driven dynamics dominate laser thrombolysis
Author(s): Robert P. Godwin; Edward J. Chapyak; Scott A. Prahl; HanQun Shangguan
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Paper Abstract

Mass removal experiments have been performed at the Oregon Medical Laser Center with 10 to 100 mJ 1 microsecond laser pulses at optical wavelengths. Above the energy threshold for bubble formation, the laser mass ablation efficiency ((mu) g/mJ) for removal of gel surrogate thrombus is nearly constant for a given experimental geometry and gel absorption coefficient. The efficiency in 'contact' experiments, in which the optical fiber delivering the energy is in close proximity to the absorbing gel, is approximately three times that of 'non-contact' experiments, in which the optical fiber is approximately 1 mm from the gel. Mass removal occurs hundreds of microseconds after the laser deposition. Experimental data and numerical simulations are consistent with the hypothesis that jet formation during bubble collapse plays a dominant role in mass removal. This hypothesis suggests a model in which the mass removed scales linearly with the maximum bubble volume and explains the distinctive features, including the magnitude, of the mass removal.

Paper Details

Date Published: 1 July 1998
PDF: 8 pages
Proc. SPIE 3245, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VIII, (1 July 1998); doi: 10.1117/12.312278
Show Author Affiliations
Robert P. Godwin, Los Alamos National Lab. (United States)
Edward J. Chapyak, Los Alamos National Lab. (United States)
Scott A. Prahl, Oregon Medical Laser Ctr./Providence St. Vincent Hospital (United States)
HanQun Shangguan, Oregon Medical Laser Ctr./Providence St. Vincent Hospital (United States)


Published in SPIE Proceedings Vol. 3245:
Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VIII
Graham M. Watson; Reza S. Malek; Aaron P. Perlmutter; Penny J. Smalley; Sharon L. Thomsen; Harvey Lui; Lawrence S. Bass; R. Rox Anderson; Lou Reinisch; C. Gaelyn Garrett; Kenneth Eugene Bartels; Lloyd P. Tate; R. Rox Anderson; Kenneth Eugene Bartels; Lawrence S. Bass; C. Gaelyn Garrett; Kenton W. Gregory; Harvey Lui; Reza S. Malek; Aaron P. Perlmutter; Lou Reinisch; Penny J. Smalley; Lloyd P. Tate; Sharon L. Thomsen; Graham M. Watson, Editor(s)

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