Controlling Parameters for Plasmonic Photothermal Ablation of a Tumor

This paper investigates the controllable therapeutic parameters for plasmonic photothermal ablation of a tumor with an objective to specify the parameters (irradiation intensity, irradiation duration, nanoparticle concentration) based on spatial distribution and accumulation of nanoparticles within a tumor. In this study, a melanoma surrounded by healthy tissue is analyzed. Monte Carlo method, Beer's law, and Pennes' bioheat equation are used to compute spatiotemporal thermal ablation zones. Results show that depending on spatial extent of nanoparticle loaded region of a tumor as well as nanoparticle concentration, different ablation zones are attained within tumor. It is shown that a nanoparticle concentration of 0.0001% embedded within 2-3-mm thick tumor periphery, along with irradiation intensity of 1 W/cm2 for duration of 110 s, is required to attain thermal ablation for the considered tumor sizes of 20-40 mm diameter. For lesser extent of nanoparticle loaded region, it is not possible to attain thermal ablation even with higher nanoparticle concentrations. Further it is shown that, for future clinical application of such therapy, through intravenous delivery of nanoparticles, a tumor must possess a certain spatial extent of vascularized region to facilitate the accumulation of nanoparticles in desired concentration for thermal ablation.