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Proceedings Paper

Wavelength-dependent scattering of light during Nd:YAG laser heating of porcine septal cartilage
Author(s): Reshmi Basu; Brian Jet-Fei Wong M.D.; Steen J. Madsen
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Paper Abstract

Heat alters the bulk physical properties of cartilage tissue, including the optical scattering and absorption coefficients. The purpose of this investigation was to measure wavelength dependent scattering of light using three different probe lasers (λ= 488 nm, 670 nm, 808 nm) during Nd:YAG laser (λ= 1.32 micrometers , 50 Hz pulse repetition rate) heating of porcine septal cartilage. An integrating sphere was used to collect diffusely backscattered light from these probe lasers and three lock- in amplifiers were used to discriminate between the different signals. Peak signal intensity of the backscattered light was observed at different temperature depending on the probe laser wavelength and specimen thickness. The observed changes are unlikely due to axial thermal gradients created during Nd:YAG laser heating and do not correlate with the fluence distribution of the three probe laser wavelengths evaluated. The observed wavelength dependent differences suggest that tissue matrix alterations during heating are due to macromolecular conformation changes that occur on the scale of the wavelength of the probe laser light. As changes in the bulk properties of cartilage can be inferred by using simple non-contact techniques such as light scattering, the characterization of the wavelength dependence of these phenomena will become increasingly important.

Paper Details

Date Published: 9 July 2001
PDF: 10 pages
Proc. SPIE 4257, Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical, (9 July 2001); doi: 10.1117/12.434728
Show Author Affiliations
Reshmi Basu, Beckman Laser Institute and Medical Clinic (United States)
Brian Jet-Fei Wong M.D., Beckman Laser Institute and Medical Clinic (United States)
Steen J. Madsen, Univ. of Nevada/Las Vegas (United States)

Published in SPIE Proceedings Vol. 4257:
Laser-Tissue Interaction XII: Photochemical, Photothermal, and Photomechanical
Donald Dean Duncan; Donald Dean Duncan; Steven L. Jacques; Peter C. Johnson; Peter C. Johnson, Editor(s)

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