The effects of gold nanoparticles characteristics and laser irradiation conditions on spatiotemporal temperature pattern of an agar phantom: A simulation and MR thermometry study

Abstract

In this paper, the effects of parameters related to gold nanoparticles (type, size, and concentration) and the laser parameters on spatiotemporal temperature pattern of an agar phantom during a photothermal therapy (PTT) procedure were modeled and then experimentally verified. Eight agar phantoms loaded by gold nanoparticles were made. An agar phantom without any nanoparticles was also considered as the control. Different sizes of two types of gold nanoparticles (spherical and silica-gold core shell) at various concentrations were studied. The phantoms were irradiated by various laser powers for 5 min. The temperature changes in each phantom was firstly calculated using COMSOL Multiphysics software. Also, each phantom was irradiated by laser and MR thermometry was performed to validate the simulation results. A reasonable correlation between simulation and MR thermometry was obtained (R = 0.92). The error interval between calculations and experiments was ranged from ±3 to ±6. It was clearly evident that laser irradiation conditions and nanoparticle characteristics affected the temperature rise profile. Spherical 20 nm gold nanoparticles had better thermal efficiency and generated higher level of heat. The protocol suggested in this study may be appropriate to make a pre-clinical calculation and effect visualization for any nanoparticles-based PTT procedure before entrance into the clinics. © 2019 Elsevier Gmb