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Laser thrombolysis using long pulse frequency‐doubled Nd:YAG lasers
Author(s) -
Viator John A.,
Prahl Scott A.
Publication year - 1999
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1999)25:5<379::aid-lsm3>3.0.co;2-b
Subject(s) - ablation , laser , dye laser , materials science , laser ablation , optics , biomedical engineering , pulse duration , medicine , physics
Background and Objective Laser thrombolysis is a means for clearing blood clots in occluded arteries. Many researchers have studied the mechanisms of clot ablation, and research clinicians have used the technique to treat myocardial infarction with a number of different laser systems. Specifically, a 1‐μsec pulsed dye laser has been used clinically to remove blood clots in coronary arteries. As a comparative study, the ablation characteristics of lasers with pulse durations in the ranges of 50–150 μsec and 2–10 msec were investigated. Two frequency‐doubled Nd:YAG lasers at 532 nm were used in this study. Ablation threshold and ablation efficiency of gel phantoms and thrombus using these two lasers were measured and compared with the results of the pulsed dye laser. The pulsed dye laser in this study operated at 522 nm. Study Design/Materials and Methods Gelatin samples with 150 cm −1 absorption coefficient at 532 nm and animal clot were confined to 3‐mm silicone tubes to measure ablation parameters. Additional samples with 150 cm −1 absorption coefficient at 522 nm were prepared for use with the pulsed dye laser. A fluorescence technique and photographic bubble detection were used to determine ablation threshold. A spectrophotometric technique was used to determine ablation efficiency. Results The ablation threshold of the gel phantoms for all three lasers was determined to be 17 ± 2 mJ/mm 2 . Ablation efficiency for the gel phantoms was 1.7 ± 0.1 μg/mJ. Clot had an ablation efficiency of 2.9 ± 1.0 μg/mJ. Conclusions Ablation threshold and efficiency are independent of laser pulse duration for 1‐μsec, 50–150‐μsec, and 2–10‐msec pulses ( P < 0.05). Lasers Surg. Med. 25:379–388, 1999. © 1999 Wiley‐Liss, Inc.