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Proceedings Paper

Er:YAG laser radiation for soft and hard urological tissue treatment
Author(s): Petr Koranda; Helena Jelínkova; Michal Němec; Oto Köhler; Pavel Drlík; Jan Pokorný; Mitsunobu Miyagi; Katsumasa Iwai; Yi-Wei Shi; Yuji Matsuura
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Paper Abstract

Er:YAG laser (wavelength 2.94 μm) operating both in free-running and Q-switched regime was designed and developed for the purpose of ureter wall perforation or incision, and urinary stones fragmentation. Component of this system was a special transfer part consisted of a cyclic olefin polymer-coated silver (COP/Ag) hollow glass waveguide (inner/outer diameter 700/850 μm or 320/450 μm) with a sealed cap for a contact treatment. Maximum pulse interaction energy and length for free-running Er:YAG laser were 100 mJ and 200 μs, respectively (corresponding intensity was 130 kW/cm2 for the 700 μm waveguide and 500 kW/cm2 for the 320 μm waveguide). Maximum interaction pulse energy and length in Q-switched regime were 30 mJ and 70 ns, respectively (corresponding intensity was 111 MW/cm2 for the 700 μm waveguide and 357 MW/cm2 for the 320 μm waveguide). Basic interaction characteristics and parameters of ureter wall perforation and urinary stones fragmentation were found. For that reason the number of pulses needed for the perforation of the ureter wall tissue (thickness ~1mm), ablation threshold and ablation rate were measured for free-running and Q-switched Er:YAG laser radiation. Subsequently, the investigated tissue samples were histologically evaluated after the interaction. The ablation rate of the Q-switched Er:YAG laser radiation was higher compared to the free-running radiation. The application of Q-switched Er:YAG laser radiation on ureter tissue resulted in minimum tissue alteration (up to 50 μm from the surface) without any influence on the deeper layers. The possibility of urinary stones perforation with free-running Er:YAG laser radiation (with maximum interaction energy) was also demonstrated.

Paper Details

Date Published: 22 February 2006
PDF: 9 pages
Proc. SPIE 6078, Photonic Therapeutics and Diagnostics II, 60781E (22 February 2006); doi: 10.1117/12.645926
Show Author Affiliations
Petr Koranda, Czech Technical Univ. (Czech Republic)
Helena Jelínkova, Czech Technical Univ. (Czech Republic)
Michal Němec, Czech Technical Univ. (Czech Republic)
Oto Köhler, Central Military Hospital (Czech Republic)
Pavel Drlík, Central Military Hospital (Czech Republic)
Jan Pokorný, Central Military Hospital (Czech Republic)
Mitsunobu Miyagi, Sendai National College of Technology (Japan)
Katsumasa Iwai, Sendai National College of Technology (Japan)
Yi-Wei Shi, Fudan Univ. (Japan)
Yuji Matsuura, Tohoku Univ. (Japan)


Published in SPIE Proceedings Vol. 6078:
Photonic Therapeutics and Diagnostics II
Kenton W. Gregory; Nikiforos Kollias; Reza S. Malek; Michael D. Lucroy; Henry Hirschberg; Brian Jet-Fei Wong; Eugene A. Trowers; Werner T.W. de Riese; Justus F. R. Ilgner; Steen J. Madsen; Lloyd P. Tate; Haishan Zeng; Guillermo J. Tearney; Bernard Choi, Editor(s)

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