| Project/Area Number |
15500309
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Tohoku University |
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Principal Investigator |
SHI Yi-wei Tohoku University, Graduate School of Engineering, Associate professor, 大学院・工学研究科, 助教授 (90323063)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAGI Mitsunobu Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (90006263)
MATSUURA Yuji Tohoku University, Graduate School of Engineering, Associate professor, 大学院・工学研究科, 助教授 (10241530)
IWAI Katsumasa Sendai National College of Technology, Assistant professor, 助手 (10361130)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | output device / hollow optical fiber / multiwavelength / multifunctional / underwater delivery / laser / infrared / calculus / 空中ファイブ / 赤外レーザ / パイロット光 / シーリングキャプ / 出射先端装置 / 結石破砕 |
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| Research Abstract |
(1)Hollow optical fiber has found wide applications in industrial and medical fields. A cyclic olefin polymer-coated silver (COP/Ag) hollow optical fiber is one of the most competent candidates for medical applications because of the properties of low transmission loss, non-toxicity, little aging effect and low cost. For infrared laser light delivery in hollow fiber, a pilot beam is often required to avoid laser hazard. We have improved the fabrication techniques to reduce the surface roughness of silver and polymer layers. Low loss has been obtained for the hollow fiber in visible and near-infrared regions as well as in middle infrared region. Pilot beam and multiwavelength infrared laser beams were delivered with low loss simultaneously.
(2)An Er:YAG laser light delivery system composed of a polymer-coated silver hollow waveguide and a quartz sealing cap has been developed for calculus fragmentation. Sealing caps with various distal-end geometries were fabricated, and the focusing eff
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ects of these caps for Er:YAG laser light were measured both in air and in water. Owing to the high power capability of the quartz sealing caps, a beam of Er:YAG laser light with an output energy of 200 mJ and a repetition rate of 10 Hz was successfully transmitted in saline solution by using the system. Calculus fragmentation experiments conducted in vitro showed that the delivery system is suitable for medical applications in lithotripsy. We also found that the cap with a focusing effect is more effective in cutting calculi. The deterioration of the sealing caps after the calculus fragmentation is also discussed.
We have experimentally quantified calculus fragmentation by Er:YAG laser light. Er:YAG laser light was delivered to an underwater target through a sealed hollow optical fiber. Fragmentation efficiency was obtained for an alumina ball used as a calculus model when sealing caps with various focusing effects were used. Three types of human calculi were analyzed and their absorption properties at the wavelength of Er:YAG laser light were obtained. The relationships among the absorption properties, calculus constituents, and fragmentation efficiency are discussed.
(3)A sealing cap had been proposed as an output device for hollow optical fibers in delivering laser light underwater. Properties of sealing cap were experimentally discussed when used in ablation on soft tissue for Er:YAG laser. A self-cleaning effect of the sealing cap was observed when various targets were used for different laser light power. Debris from pork fat formed a uniform oil layer on the output surface of the cap, and the oil layer is relatively transparent in Er:YAG laser light wavelength band. When the target was pork muscle, almost no debris could attach on the surface of the cap. The self-cleaning effect was more obvious when ablation was conducted underwater because of the protection of the water film between the target and the cap's surface. Less
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