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Titolo:
EFFECT OF PULSE DURATION ON BUBBLE FORMATION AND LASER-INDUCED PRESSURE WAVES DURING HOLMIUM LASER-ABLATION
Autore:
JANSEN ED; ASSHAUER T; FRENZ M; MOTAMEDI M; DELACRETAZ G; WELCH AJ;
Indirizzi:
UNIV TEXAS,BIOMED ENGN PROGRAM,ENS 614A AUSTIN TX 78712 UNIV TEXAS,MED BRANCH,BIOMED LASER & SPECT PROGRAM GALVESTON TX 77555 SWISS FED INST TECHNOL,LAB APPL OPT CH-1015 LAUSANNE SWITZERLAND UNIV BERN,INST PHYS APPL CH-3112 BERN SWITZERLAND
Titolo Testata:
Lasers in surgery and medicine
fascicolo: 3, volume: 18, anno: 1996,
pagine: 278 - 293
SICI:
0196-8092(1996)18:3<278:EOPDOB>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
TISSUE ABLATION; SHOCK-WAVES; WATER;
Keywords:
ACOUSTICS; BUBBLE; CAVITATION; INFRARED LASER; PULSE LENGTH; TISSUE PHANTOMS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
37
Recensione:
Indirizzi per estratti:
Citazione:
E.D. Jansen et al., "EFFECT OF PULSE DURATION ON BUBBLE FORMATION AND LASER-INDUCED PRESSURE WAVES DURING HOLMIUM LASER-ABLATION", Lasers in surgery and medicine, 18(3), 1996, pp. 278-293

Abstract

Background and Objective: One concern during laser ablation of tissueis the mechanical injury that may be induced in tissue in the vicinity of the ablation site. This injury is primarily due to rapid bubble expansion and collapse or due to laser-induced pressure waves. In this study, the effect of laser pulse duration on the thermodynamics of bubble formation and accompanying acoustic pressure wave generation has been investigated. Study Design/Materials and Methods: Q-switched holmium:YAG laser pulses (pulse duration 500 ns, pulse energy 14 mJ) and free-running holmium:YAG laser pulses (pulse duration 100-1,100 mu s, pulse energy 200 mJ) were delivered in water and tissue phantoms via a 200- and 400-mu m fiber, respectively. The tissue phantoms consisted ofpolyacrylamide gels with varying mechanical strengths. Bubble formation was recorded with a fast flash photography setup, while acoustic transients were measured with a needle hydrophone. Results: It was observed that, as the pulse length was increased the bubble shape changed from almost spherical for Q-switched pulses to a more elongated cylinder shape for longer pulse durations. The bubble expansion velocity was larger for shorter pulse durations. Only the Q-switched pulse induced a measurable thermo-elastic expansion wave. All pulses that induced bubble formation generated pressure waves upon collapse of the bubble ingels as well as in water. However, the magnitude of the pressure wavedepended strongly on the size and geometry of the induced bubble. Conclusion: The magnitude of the collapse pressure wave decreased as laser pulse duration increased. Hence it may be possible to reduce collateral mechanical tissue damage by stretching the holmium laser pulse. (C) 1996 Wiley-Liss, Inc.

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Documento generato il 02/12/20 alle ore 15:04:37