Study on Simulation Model for Nanoparticle Enhanced Laser Ablation Based on Monte Carlo Methods
Objective To design a numerical simulation model of laser ablation and determine the laser ablation treatment for brain tumors,and to determine the effects of ablation time,laser power and aqueous solution of gold nanoparticles on laser ablation.Methods In this study,a simplified brain tumor geometric model was established,and the photon distribution in brain tissue was simulated by the Monte Carlo calculation method to determine laser energy deposition.Then,the Pennes biological heat transfer model was used to calculate the temperature increase process of spheroid tumors embedded in cylindrical human brain tissue.The Arrhenius integral was combined with the heat transfer model to calculate the thermal damage of the tissue and determine the laser ablation scheme.Gold nanoparticles were introduced in the model where the thermal damage range exceeded the tumor volume,and the feasibility of gold nanoparticles in reducing the damage of surrounding healthy tissues was explored.Results Increasing the laser power or ablation time increased the maximum temperature during the ablation process and the range of thermal damage.For the spheroid brain tumor with a diameter of 10 mm assumed in this study,when the ablation time was 300 s,the laser power was 3 W,the ablation time was 180 s,and the laser power was 5 W,the spheroid tumor was completely ablated.Gold nanoparticles were injected into the tumor,assuming that the gold nanoparticles were evenly distributed in the tumor,the selected ablation combination with a demelting time of 180 s laser power of 5 W and when did not add gold nanoparticles,the volume of thermal damage was 1.98 cm3,the damage rate to surrounding healthy tissues was 2.96%,the thermal damage volume after adding gold nanoparticles in the same combination was 0.95 cm3,and the damage rate to surrounding healthy tissues was 0.88%.Conclusion The numerical simulation model established in this study has a certain reference role in determining the laser ablation parameters.Increasing laser power and ablation time can increase the volume of thermal damage and increase the maximum ablation temperature,while the addition of gold nanoparticles can reduce the thermal damage to healthy tissues.
brain tumorsMonte Carlo methodlaser ablationnumerical simulationbiological heat transfer
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