Thermal Assessment of ICG-treated Aortic Media during Diode Laser Exposure

Abstract

This study was designed to investigate a combination treatment of Diode laser (wavelength: 808nm) with Indocyanine green (ICG), as an photoenhancement dye. Three different concentrations of ICG (0.5, 3.0, 10.0mg/ml) and three different staining periods (20sec, 1min, 5min) were applied to stain the fresh human aorta after endarterectomy to find out an optimal condition. Spectrophotometric and histological examinations revealed that the optimal parameter for tissue staining was 3.0mg/ml of ICG concentration and five minutes of staining period at 37°C.
Diode laser was applied for the previously stained and the non-stained aortic media in four different laser energy (4.7, 9.3, 18.6 and 27.9w/cm2) for five seconds. Thermal camera showed a real-time change of surface temperature. The peak temperature for the stained specimen at 27.9w/cm2 was 219±15°C, and the peak temperature for the non-stained one was 26±1°C at the same energy. In conclusion, the combination treatment of Diode laser with Indocyanine green participates to absorb and localize laser energy, that is, minimizing thermal injury.