Effects of magnetic nanoparticle diffusion on microwave ablation treatment: A numerical approach

Microwave ablation (MWA) is a targeted process that kills malignant cells by heating a tumor region without damaging the surrounding tissue. The microwave heating of tumors can be improved by the injection of magnetic nanoparticles (MNPs). The effectiveness of this technique, evaluated by the dimensions of the ablation zone, is related to the MNPs' concentration and the MWA input power and frequency. This work investigates how MNP dissipation affects the temperature profile of solid tumors undergoing MWA. The influences of the injection site, diffusion duration, and the size of the particles are investigated. The temperature profile is numerically estimated by solving coupled electromagnetic field and bio-heat transfer equation using the finite element method. Results demonstrate that the injection process has an essential role in temperature distribution, and that the assumption of uniform drug distribution in the tumor is not a prerequisite. Although increasing the diffusion time decreases the maximum temperature difference from 76.7 degrees C to 62.6 degrees C, the radius of the ablation zone increases 1.4 times, because MNPs seeping throughout the tumor increase heat penetration. Results also demonstrate that, compared to 20 nm nanoparticles, 10 nm ones increase the area of ablation by 30%, due to their better diffusion in the tumor. This investigation concludes that diffusion of MNPs in a tumor can improve MWA efficiency.