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Proceedings Paper

Myocardium tissue ablation with nanosecond ultraviolet pulses: in-vitro study with porcine myocardium tissues
Author(s): Tomoaki Shimada; Shunichi Sato; Miya Ishihara; Tsunenori Arai; Takemi Matsui; Akira Kurita; Makoto Kikuchi; Hitoshi Wakisaka; Hiroshi Ashida; Minoru Obara
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Paper Abstract

To investigate the optimum irradiation conditions for the transmyocardial laser revascularization (TMLR), ablation characteristics have been explored in vitro with porcine myocardium tissues. With a nanosecond optical parametric oscillator (OPO), the ablation depth and the thickness of thermally damaged tissue were measured at a constant peak intensity or fluence in the ultraviolet spectral region of 230 - 400 nm. It was found that at a peak intensity of 80 MW/cm2, the ablation depth steeply increased for < 300 nm, while the thickness of thermally damaged tissue decreased with decreasing the wavelength. To understand the wavelength dependence of the ablation characteristics, we measured the optical properties of the tissue. This showed that the total attenuation coefficient largely increased with decreasing the wavelength for < 300 nm. Therefore, it is considered that at the shorter wavelengths the optical energy density deposited in the tissue would be high enough to ablate the whole region of the light-penetrated tissue. However, the wavelength dependence might be changed at some higher intensities or fluences. But our experiment using the 3rd and 4th of a Q- switched Nd:YAG laser, the shorter wavelength (266 nm) still gave the deeper ablation for up to 2 - 5 J/cm2. The influence of photochemical effects on the ablation mechanism is also discussed.

Paper Details

Date Published: 13 June 2000
PDF: 6 pages
Proc. SPIE 3914, Laser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical, (13 June 2000); doi: 10.1117/12.388029
Show Author Affiliations
Tomoaki Shimada, Keio Univ. (Japan)
Shunichi Sato, National Defense Medical College Research Institute (Japan)
Miya Ishihara, National Defense Medical College (Japan)
Tsunenori Arai, National Defense Medical College (Japan)
Takemi Matsui, National Defense Medical College Research Institute (Japan)
Akira Kurita, National Defense Medical College Research Institute (Japan)
Makoto Kikuchi, National Defense Medical College (Japan)
Hitoshi Wakisaka, National Defense Medical College Research Institute (Japan)
Hiroshi Ashida, National Defense Medical College Research Institute (Japan)
Minoru Obara, Keio Univ. (Japan)


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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