Tissue colouring with exogenous chromophores to extend surgical use of 808 nm diode lasers

Ovidio Marangoni, Mauro Melato

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Lasers with a wavelength between 351-1064 nm, 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 (PDT), in welding, and more recently for epilation. The aim of our study was to assess the effectiveness of a wavelength of 808 nm 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 808 nm. We tested the diode laser 808 nm, (Eufoton - Trieste) at focussed powers of 1, 2, 3, 5, 7 W in cw, for 1, 2, 3, 5, 7, 10 sec on skin specimens stained with 1% methylene blue in a small-spot sequence (2 mm diameter). At low powers the destructive effect was highly concentrated, both in depth and laterally, while greater intensities resulted in marked destruction even after a short irradiation time. The use of exogenous chromophores increases absorption and reduces laser energy transmission and scatter. This study confirms that the selectivity of 808 nm 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.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherSociety of Photo-Optical Instrumentation Engineers
Number of pages6
Publication statusPublished - 2000
EventLaser Florence '99 - A Window on the Laser Medicine World - Florence, Italy
Duration: Oct 28 1999Oct 31 1999


OtherLaser Florence '99 - A Window on the Laser Medicine World
CityFlorence, Italy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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