Exogenous chromophores for the argon and Nd:YAG lasers: a potential application to laser-tissue interactions.
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/cm2, 60 s and 488/514 nm, 400 mW, 10.5 W/cm2, 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 degrees C v. 20 degrees C at 60 s, P less than 0.001, 2-way ANOVA). Three of the four infrared dyes behaved similarly (40-70 degrees C v. 20 degrees C, P less than 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.
Brooks
S G
SG
Cardiac Research Unit, Killingbeck Hospital, Leeds, England.
Ashley
S
S
Fisher
J
J
Davies
G A
GA
Griffiths
J
J
Kester
R C
RC
Rees
M R
MR
D000042:Absorption; D000714:Anastomosis, Surgical; D000818:Animals; D001128:Argon; D001831:Body Temperature; D004396:Coloring Agents / Q000493:pharmacokinetics*; D003331:Coronary Vessels; D053685:Laser Therapy; D009354:Neodymium; D013552:Swine; D014656:Vascular Surgical Procedures; D015019:Yttrium
D004396:Coloring Agents; D009354:Neodymium; D015019:Yttrium; D001128:Argon