Detection of pre-charring optical behavior at a laser catheter-tip in blood: Ex vivo and in vivo study

Mei Takahashi, Arisa Ito, Takuro Kajihara, Tsunenori Arai

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

1 Citation (Scopus)


We studied a pre-charring optical behavior of blood at a laser catheter-tip during a red laser irradiation (663 nm, CW) with around 50 W/cm2 in blood to prevent charring at the laser catheter-tip. The laser irradiated red-blood-cell shape changes were microscopically observed. A round formation, aggregation, and hemolysis were found until blood charring (ex vivo). A time-history of diffuse-reflected light power and transmitted light power from a thin blood layer which was irradiated by the red laser were measured with microscope optics to investigate the charring process. The diffusereflected light power decreased following a gentle peak before the charring. This decrease indicated the pre-charring behavior which might be induced by scattering and absorption changes due to red-blood-cell degenerations described above. Using the laser catheter located in porcine heart, we successfully detected the pre-charring behavior by a backscattering light power (in vivo). We demonstrated charring prevention availability with the laser power control (ex vivo). We think that the backscattering light power measurement and laser power control via the laser catheter might be useful to detect pre-charring behavior, and to prevent the charring for therapeutic laser irradiation in blood under catheterization such as arrhythmia treatment with photodynamic therapy.

Original languageEnglish
Title of host publicationOptical Interactions with Tissue and Cells XXII
Publication statusPublished - 2011 Apr 29
EventOptical Interactions with Tissue and Cells XXII - San Francisco, CA, United States
Duration: 2011 Jan 242011 Jan 26

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherOptical Interactions with Tissue and Cells XXII
Country/TerritoryUnited States
CitySan Francisco, CA


  • Blood charring
  • Charring prevention
  • Laser irradiation
  • Pre-charring detection

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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