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Effects of varying argon ion laser intensity and exposure time on the ablation of atherosclerotic plaque
Author(s) -
Strikwerda Sipke,
BottSilverman Corinne,
Ratliff Norman B.,
Goormastic Marlene,
Cothren Robert M.,
Costello Ben,
Kittrell Carter,
Feld Michael S.,
Kramer John R.
Publication year - 1988
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/lsm.1900080112
Subject(s) - fluence , ablation , laser , materials science , argon , intensity (physics) , continuous wave , laser ablation , coagulative necrosis , optics , nuclear medicine , chemistry , medicine , pathology , physics , organic chemistry
Using continuous wave (CW) argon ion laser light, a total of 253 laser exposures of varying power (1.5, 3, 5, 8 or 10 W) and duration (20–1,333 ms) were delivered to four segments of human atheromatous aorta obtained at autopsy. Exposure conditions were controlled by using an optically shielded laser catheter that provided a 500 μm spot of light of known power. Two thresholds for consistently reproducible ablation could be defined–an intensity threshold at 25.5 W/mm 2 and a fluence threshold at 3.2 J/mm 2 . Above threshold, a fluence of 5.1 J/mm 2 was found to produce the most efficient ablation, ie, removed the greatest volume (mm 3 ) per energy delivered (J) compared to other fluence levels employed (p < 0.0001). Between aortic segments, however, considerable variability in efficiency (mm 3 /J) was observed, possibly owing to different optical properties and/or plaque composition. Low‐intensity laser radiation produced inconsistent ablation and extensive coagulation effects to surrounding tissue. When a fluence of 5.1 J/mm 2 was constructed with a high‐intensity laser beam and a short exposure time, consistent and efficient tissue removal resulted without histologic evidence of coagulation necrosis.