Exogenous chromophores for the argon and Nd:YAG lasers: A potential application to laser-tissue interactions

✍ Scribed by Mr. Stephen G. Brooks; Simon Ashley; John Fisher; Gwilym A. Davies; John Griffiths; Ralph C. Kester; Michael R. Rees

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 1005 KB
• Volume: 12
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.1900120309

✦ Synopsis

Abstract

Chromophore dyes can be employed to modify laser‐tissue interaction. A number of dyes have been investigated for their effect on the absorption and transmission of argon and Nd:YAG laser energy by vascular tissue in vitro. Three histological dyes have been assessed as potential chromophores for the argon laser and four infrared dyes for the Nd:YAG. Segments of porcine coronary artery to which dye had been applied were lased (1,064 nm, 2.5 W, 83 W/cm^2^, 60 s and 488/514 nm, 400 mW, 10.5 W/cm^2^, 60s) and the tissue temperature measured remotely using an infrared thermometer. In addition, energy transmission was measured with a photodiode and tissue morphological changes assessed histologically.

All three argon dyes significantly increased energy absorption (typically 60°C v. 20°C at 60 s, P < 0.001, 2‐way ANOVA). Three of the four infrared dyes behaved similarly (40–70°C v. 20°C, P < 0.001). All dyes significantly increased the initial rate of rise in tissue temperature during lasing. A reduction in energy transmission was observed for each of the Argon dyes but not for the Nd:YAG dyes. Histological evidence of thermal damage in control tissue first occurred for the argon and Nd:YAG lasers at 800 mW and 7.5 W without chromophore and at 400 mW and 2.5 W with the chromophore, respectively.

A number of effective chromophores have therefore been identified at each wavelength. © 1992 Wiley‐Liss, Inc.