Laser dosimetry for thermal fusion of plaque-wall separations during laser balloon angioplasty (LBA) is dependent upon the optical properties of the atheromatous arterial wall during one or more exposures to cw Nd:YAG laser radiation. An integrating sphere technique was used to measure relative transmission and reflection continuously during irradiation of human postmortem atheromatous aortic sections. Tissue luminal surface temperature was recorded continuously with a thermographic video imager during repetitive 20-30-sec, 8-15-watt exposure of a 3-mm nominal spot. In all specimens, transmission fell progressively during each exposure to 10-70% of baseline values. This effect was reversible with normalization of transmission during the initial phase of each subsequent exposure. Changes in transmission were inversely related to temperature over a 50-170°C range, whereas relative reflection remained constant. Accompanying reversible transmission changes was the observation that the weld strength of plaque-aortic wall separations was unchanged by repetitive laser welding and tissue separation of individual sections. In conclusion, temperature-dependent reversible optical and physical properties of plaque occur during exposure to 1.06 μm cw laser radiation.
|Original language||English (US)|
|Number of pages||9|
|Journal||Lasers in Surgery and Medicine|
|State||Published - 1988|
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