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Proceedings Paper

Bubble formation during pulsed laser ablation: mechanism and implications
Author(s): Ton G. J. M. van Leeuwen; E. Duco Jansen; Massoud Motamedi; Ashley J. Welch; Cornelius Borst
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Paper Abstract

Holmium ((lambda) equals 2.09 micrometers ) and excimer ((lambda) equals 308 nm) lasers are used for ablation of tissue. In a previous study it was demonstrated that both excimer and holmium laser pulses produce fast expanding and collapsing vapor bubbles. To investigate whether the excimer induced bubble is caused by vaporization of water, the threshold fluence for bubble formation at a bare fiber tip in water was compared between the excimer laser (pulse length 115 ns) and the Q-switched and free-running holmium lasers (pulse length 1 microsecond(s) to 250 microsecond(s) , respectively). To induce bubble formation by excimer laser light in water, the absorber oxybuprocaine-hydrochloride (OBP-HCl) was added to the water. Fast flash photography was used to measure the threshold fluence as a function of the water temperature (6 - 90 degree(s)C) at environmental pressure. The ultraviolet excimer laser light is strongly absorbed by blood. Therefore, to document the implications of bubble formation at fluences above the tissue ablation threshold, excimer laser pulses were delivered in vitro in hemoglobin solution and in vivo in the femoral artery of the rabbit. We conclude that the principal content of the fast bubble induced by a 308 nm excimer laser pulse is water vapor. Therefore, delivery of excimer laser pulses in a water or blood environment will cause fast expanding water vapor bubbles, which may induce mechanical damage to adjacent tissue.

Paper Details

Date Published: 7 July 1993
PDF: 10 pages
Proc. SPIE 1882, Laser-Tissue Interaction IV, (7 July 1993); doi: 10.1117/12.147658
Show Author Affiliations
Ton G. J. M. van Leeuwen, Interuniv. Cardiology Institute of the Netherlands (Netherlands)
E. Duco Jansen, Univ. of Texas/Austin (United States)
Massoud Motamedi, Univ. of Texas Medical Branch/Galveston (United States)
Ashley J. Welch, Univ. of Texas/Austin (United States)
Cornelius Borst, Univ. Hospital Utrecht (Netherlands)

Published in SPIE Proceedings Vol. 1882:
Laser-Tissue Interaction IV
Steven L. Jacques; Abraham Katzir, Editor(s)

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