Laser heating numerical simulation of titanium-containing optothermal fiber converter and vein wall during endovasal laser coagulation

Abstract

Subject of Research. The paper presents numerical methods that first studied laser heating of titanium-containing optothermal fiber converter and vein wall, as well as the effect of thermal damage of the vein wall during endovasal laser coagulation with different average power of 980 nm semiconductor laser and the traction speed of the converter inside the vein. Method. Models and conditions for numerical simulation of optical and thermal physical processes were formulated, occurring during endovasal laser coagulation of veins using titanium-containing optothermal fiber converter. The Monte Carlo method was used in optical modeling. The initial-edge task for a non-linear model of radiation-conductive heat transport with moving sources of radiation was analyzed at thermal simulation by the method of finite dispositions. The effect of vein wall thermal damage was assessed as a result of solving the Arrhenius equation. Main Results. The titanium-containing optothermal fiber converter can be used for endovasal laser coagulation of veins by radiation of 980 nm laser with average power up to 20 W. Laser radiation is almost completely absorbed by the converter. With the simultaneous start of laser radiation and the beginning of traction, the temperature of the vein wall does not immediately reach the maximum value; the waiting time can reach units and even tens of seconds. The temperature inside converter exceeds 250 °C. The optimal combinations of average laser power and titanium-containing converter traction speed are defined for uniform coagulation of the vein wall. Practical Relevance. The results can be used in the development of laser methods and devices for endovasal laser coagulation of veins.