Abstract

Endovenous laser ablation (EVLA) is a common treatment method for varicose vein. However, the precise irradiation dose for EVLA is not understood quantitatively. The objective of this study is to evaluate EVLA quantitatively based on optical properties of the varicose vein tissue, and compare the efficacy and the safety at wavelengths of 980 nm and 1470 nm. A human varicose vein tissue was used as a sample. The samples were irradiated by using the 980 nm and 1470 nm laser diodes in various irradiation parameters. The power density was varied from 260 to 1710 W/cm² and the irradiation time was varied from 3 to 10 s. The optical properties of samples were determined by using a double integrating sphere and an inverse Monte Carlo method. The optical penetration depth of samples was estimated from the optical properties. In the 980 nm laser irradiation, the initial shrinkage of the tissue was observed during laser irradiation conducted at the average energy density of 3630 J/cm² (1210 W/cm², 3 s). In the 1470 nm laser irradiation, the initial shrinkage of the tissue was observed during laser irradiation conducted at the average energy density of 2600 J/cm² (260 W/cm², 10 s). Penetration depth of the vein wall at the wavelength of 980 nm and 1470 nm were 1.3 mm and 0.22 mm, respectively. The sample irradiated with the 1470 nm laser diode showed vein shrinkage in lower energy density than the 980 nm laser irradiation. The penetration depth at the wavelength of 1470 nm was smaller than the sample thickness about 0.8 mm. These data indicate that EVLA with the 1470 nm laser diode may be more effective and safer than EVLA with the 980 nm laser diode.

© 2011 OSA/SPIE