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Proceedings Paper

Tissue coloring with exogenous chromophores to extend surgical use of 808-nm diode lasers
Author(s): Ovidio Marangoni; Mauro Melato
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Paper Abstract

Lasers with a wavelength between 351-1064nm, preset fluence and pulse duration induce a selective thermolysis of tissue chromophores. Specific exogenous chromophores, such as indocyanine green, are used in ophthalmology, in photodynamic therapy, in welding, and more recently for epilation. The aim of our study was to assess the effectiveness of a wavelength of 808nm on tissues stained with different exogenous chromophores whose absorption curves we studied by spectrophotometer. Out of five chromophores, methylene blue proved to be effective at 808nm. We tested the diode laser 808nm, at focused powers of 1, 2, 3, 5, 7 W in cw, for 1, 2, 3, 5, 7, 10 sec on skin specimens stained with 1 percent methylene blue in a small- spot sequence. At low powers the destructive effect was highly concentrated, both in depth and laterally, while greater intensities result in marked destruction even after a short irradiation time. The use of exogeneous chromophores increases absorption and reduces laser energy transmission and scatter. This study confirms that the selectivity of 808nm lasers can be 'tricked' since thermolysis is confined to the stained areas and there is less risk of damaging surrounding areas in the event of abrupt movements by either the surgeon or the patient, especially in the case of emotionally unstable or very young patients.

Paper Details

Date Published: 28 June 2000
PDF: 6 pages
Proc. SPIE 4166, Laser Florence '99: A Window on the Laser Medicine World, (28 June 2000); doi: 10.1117/12.389460
Show Author Affiliations
Ovidio Marangoni, Multilaser Diagnostica Terapeutica (Italy)
Mauro Melato, Univ. of Trieste (Italy)

Published in SPIE Proceedings Vol. 4166:
Laser Florence '99: A Window on the Laser Medicine World
Leonardo Longo; Alfons G. Hofstetter; Mihail-Lucian Pascu; Wilhelm R.A. Waidelich, Editor(s)

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