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Proceedings Paper

Dependence of laser photocoagulation on interstitial delivery parameters
Author(s): Douglas Robert Wyman; Brian C. Wilson; Kathryn Adams
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Paper Abstract

Interstitial laser photocoagulation (ILP) was performed ex vivo between tissue slabs by delivering continuous-wave laser energy from an optical fiber (400 micrometers core, plane-cut, 5 mm cladding stripped) either directly, or by depositing the energy into a 2.4 mm diameter steel sphere mounted on the fiber tip. The dependence of the size and nature of the resulting thermal coagulation lesions on the following variables were assessed: (1) energy source: Nd:YAG - 532 nm, 1064 nm +/- steel sphere, (2) tissue type: porcine muscle (light), bovine muscle (dark), (3) delivered power: P equals 1.5 - 3.0 W (porcine), 1.0 - 2.5 W (bovine), (4) exposure duration: T equals 300 - 700 s. The resulting cross-sectional ILP lesions are summarized as follows: 532 nm: elongated; central charring in bovine and porcine at all powers. 1064 nm: circular; central charring only in bovine for P >= 2.0 W, T >= 500 s, sphere: circular; central charring in bovine for P >= 1.5 W and porcine for P >= 2.0 W. These experiments confirm a recent report suggesting ILP lesion size decreases as optical penetration increases. The results indicate that ILP lesions of clinically useful size (diameter >= 8 mm) must necessarily involve central charring in heavily pigmented tissues, but ILP lesions greater than 10 mm diameter can be made without charring in lightly pigmented tissues by delivering 3.0 W of 1064 nm laser energy for 700 s.

Paper Details

Date Published: 7 July 1993
PDF: 8 pages
Proc. SPIE 1882, Laser-Tissue Interaction IV, (7 July 1993); doi: 10.1117/12.147659
Show Author Affiliations
Douglas Robert Wyman, Hamilton Regional Cancer Ctr. and McMaster Univ. (Canada)
Brian C. Wilson, Hamilton Regional Cancer Ctr. and McMaster Univ. (Canada)
Kathryn Adams, Hamilton Regional Cancer Ctr. and McMaster Univ. (Canada)

Published in SPIE Proceedings Vol. 1882:
Laser-Tissue Interaction IV
Steven L. Jacques; Abraham Katzir, Editor(s)

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