@inproceedings{8b9f4f5ae66f423b8273d0295c88cb2a,
title = "Detection of pre-charring optical behavior at a laser catheter-tip in blood: Ex vivo and in vivo study",
abstract = "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.",
keywords = "Blood charring, Charring prevention, Laser irradiation, Pre-charring detection",
author = "Mei Takahashi and Arisa Ito and Takuro Kajihara and Tsunenori Arai",
year = "2011",
month = apr,
day = "29",
doi = "10.1117/12.874622",
language = "English",
isbn = "9780819484345",
series = "Progress in Biomedical Optics and Imaging - Proceedings of SPIE",
booktitle = "Optical Interactions with Tissue and Cells XXII",
note = "Optical Interactions with Tissue and Cells XXII ; Conference date: 24-01-2011 Through 26-01-2011",
}