Liver photocoagulation with diode laser (805 nm) vs NdrYAG laser (1064 nm)

Steven L. Jacques, Sohi Rastegar, Massoud Motamedi, Sharon L. Thomsen, John Schwartz, Jorge Torres, Illka Mannonen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

46 Scopus citations


Experiments in dog and rat liver compared the 805-nm wavelength of the diode laser and the 1064-nm wavelength of the NdrYAG laser. (1) The major optical differences are in the absorption. The optical properties of dog liver were determined by integrating sphere experiments. The scattering coefficients were similar at both wavelengths, but the absorption was 3.5-fold greater for the diode laser wavelength. Consequently, the diode laser penetrated less deeply and heated the liver surface more strongly than the NdrYAG laser. (2) Blood is an major component of liver absorption. When blood accumulated in the lower region of a rat liver held sideways, surface heating (measured by infrared camera) by the diode laser increased due to increased absorption by the pooled blood. (3) Tissue optics and irradiance geometry together affect the zone of thermal coagulation caused by each laser. The sizes of coagulation lesions in rat liver in vivo indicated larger zones of coagulation with the NdrYAG laser. Our working hypothesis is that the diode laser caused greater surface heating and water evaporation which meant less energy remained in the tissue. Enlarging the spot size of irradiance should alleviate such surface overheating and evaporation losses and maximize the zone of coagulation. The similarities between the two lasers are more striking than the differences.

Original languageEnglish (US)
Title of host publicationLaser-Tissue Interaction III
EditorsSteven L. Jacques
Number of pages11
ISBN (Electronic)9780819407924
StatePublished - Aug 7 1992
EventLaser-Tissue Interaction III 1992 - Los Angeles, United States
Duration: Jan 19 1992Jan 24 1992

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherLaser-Tissue Interaction III 1992
Country/TerritoryUnited States
CityLos Angeles

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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