Title :
Photothermal-induced temperature changes in a model inner ear: a comparison of visible, infrared, and ultraviolet lasers
Author :
Wong, Brian J F ; Lee, Jon P. ; Dickinson, Mark R. ; Neev, Joseph ; Svaasand, Lars O.
Author_Institution :
Beckman Laser Inst. & Med. Clinic, California Univ., Irvine, CA, USA
fDate :
12/1/1996 12:00:00 AM
Abstract :
The temperature change in a model cylindrical vestibule (90 mm3) was measured following irradiation by argon (488-514 nm), CO2 (10.6 μm), KTP (Nd:YAG) (532 nm), Er:YAG (2.9 μm), and XeCl (308 nm) lasers. Otic capsule bone was used to simulate the otosclerotic stapes footplate, and the thickness of each specimen was machined to variable thicknesses (0.20-0.90 mm). Thermocouples were used to measure the temperature below the air-bone surface at depths of 1.0, 3.0, and 5.0 mm. The time-dependent temperature change, thermocouple position, and bone thickness were measured following single pulse application from argon, CO2, and KTP (Nd-YAG) lasers. The effect of infrared and ultraviolet lasers on vestibule fluid temperature changes were studied with several fluence and pulse sequences. The temperature change in the vestibule following pulsed laser irradiation decreased with increasing bone thickness and thermocouple depth. Laser irradiation from CO2, argon, KTP-532, XeCl, and Er:YAG lasers produced minimal (less than 5°) vestibule temperature changes. Measured temperatures were in good agreement with an analytic model, based on a solution to the bio-heat equation in semi-infinite media. The results are discussed with relevance to ear surgery
Keywords :
biological effects of laser radiation; biothermics; bone; ear; laser applications in medicine; physiological models; radiation therapy; surgery; 0.20 to 0.90 mm; 1.0 mm; 10.6 mum; 2.9 mum; 3.0 mm; 308 nm; 488 to 514 nm; 5.0 mm; 532 nm; CO2; CO2 laser; Er:YAG laser; KTiOPO4; Nd:YAG laser; XeCl; XeCl laser; YAG:Er; YAG:Nd; YAl5O12:Er; YAl5O12:Nd; air-bone surface; analytic model; bio-heat equation; bone thickness; ear surgery; infrared lasers; model cylindrical vestibule; model inner ear; otic capsule bone; otosclerotic stapes footplate; photothermal-induced temperature changes; pulsed laser irradiation; semi-infinite media; specimen thickness; thermocouple position; thermocouples; time-dependent temperature change; ultraviolet lasers; visible lasers; Argon; Bones; Ear; Laser modes; Laser transitions; Optical pulses; Position measurement; Pulse measurements; Temperature measurement; Thickness measurement;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/2944.577321
