Myocardium tissue ablation with nanosecond, ultraviolet pulses: in-vitro study with porcine myocardium tissues

Tomoaki Shimada, Shunichi Sato, Miya Ishihara, Tsunenori Arai, Takemi Matsui, Akira Kurita, Makoto Kikuchi, Hitoshi Wakisaka, Hiroshi Ashida, Minoru Obara

Research output: Contribution to journalConference articlepeer-review


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 photomechanical effects on the ablation mechanism is also discussed.

Original languageEnglish
Pages (from-to)116-121
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2000
Externally publishedYes
EventLaser-Tissue Interaction XI: Photochemical, Photothermal, and Photomechanical - San Jose, CA, USA
Duration: 2000 Jan 222000 Jan 27

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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