In vitro erbium:YAG laser lithotripsy

Kin Foong Chan, Gracie Vargas, Patricia J. Parker, Joel M.H. Teichman, Randolph D. Glickman, H. Stan McGuff, A. J. Welch

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations


The potential application of an Erbium:YAG (Er:YAG) laser (Qo = 50 mJ/pulse; τp = 275 μs; rep. rate = 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.μm2/J) in Er:YAG laser lithotripsy was about 2.4 times that of Ho:YAG laser lithotripsy (used: Qo = 500 mJ/pulse; τp = 250 μs; rep. rate = 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.

Original languageEnglish (US)
Pages (from-to)198-206
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2000
Externally publishedYes
EventLaser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical - San Jose, CA, USA
Duration: Jan 22 2000Jan 27 2000

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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