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Proceedings Paper

In-vitro Erbium:YAG laser lithotripsy
Author(s): Kin Foong Chan; Gracie Vargas; Patricia J. Parker; Joel M. H. Teichman; Randolph D. Glickman; H. Stan McGuff; Ashley J. Welch
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Paper Abstract

The potential application of an Erbium:YAG (Er:YAG) laser (Qo equals 50 mJ/pulse; (tau) p equals 275 microsecond(s) ; rep. rate equals 2, 10 Hz) with a sapphire delivery fiber for intracorporeal laser lithotripsy was explored. Preliminary measurements on calculus mass-loss and fragmentation efficiency were conducted and results were compared with that of Ho:YAG laser lithotripsy. Laser induced bubble and lithotripsy dynamics were investigated to assess the mechanism(s) involved in the fragmentation process. Results showed that the fragmentation efficiency (mass-loss/Ho - g.micrometers 2/J) in Er:YAG laser lithotripsy was about 2.4 times that of Ho:YAG laser lithotripsy (used: Qo equals 500 mJ/pulse; (tau) p equals 250 microsecond(s) ; rep. rate equals 10 Hz). Acoustic transients were found to have minimal effect during Er:YAG laser lithotripsy. Schlieren flash images suggested a predominantly photothermal mechanism due to direct laser energy absorption, which resulted in recrystallization and plume formation. These events indicated melting and chemical decomposition of the calculus composition. Another observation led to the possibility of a plasma-mediated photothermal mechanism. The 'Moses effect' facilitating pulsed mid-infrared laser delivery appeared more efficient for the Er:YAG laser than for the Ho:YAG laser. With the sapphire fiber, experimental results suggested the potential of an improved treatment modality by the Er:YAG laser for intracorporeal laser lithotripsy.

Paper Details

Date Published: 13 June 2000
PDF: 9 pages
Proc. SPIE 3914, Laser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical, (13 June 2000); doi: 10.1117/12.388046
Show Author Affiliations
Kin Foong Chan, Univ. of Texas/Austin (United States)
Gracie Vargas, Univ. of Texas/Austin (United States)
Patricia J. Parker, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Joel M. H. Teichman, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Randolph D. Glickman, Univ. of Texas Health Science Ctr. at San Antonio (United States)
H. Stan McGuff, Univ. of Texas Health Science Ctr. at San Antonio (United States)
Ashley J. Welch, Univ. of Texas/Austin (United States)


Published in SPIE Proceedings Vol. 3914:
Laser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical
Jeffrey O. Hollinger; Donald Dean Duncan; Jeffrey O. Hollinger; Donald Dean Duncan; Steven L. Jacques, Editor(s)

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