Finite Element Method Modelling of Iron - Oxide Nanoparticle Heat Generation Under Low Radio Frequency Field Conditions

Abstract

Iron-oxide based magnetic nanoparticles are used as contrast agents in magnetic resonance imaging and as magnetically induced heat generators in magnetic hyperthermia which is a non-invasive cancer treatment method based on delivering nanoparticles to the tumor site. Then, applying alternating magnetic fields generated by specifically designed coils to heat up nanoparticles, thereby killing and/or sensitizing cancer cells to other forms of cancer therapy. Efficiency is measured by heat generation capabilities of nanoparticles under minimum coil power. Therein, measuring temperature rises is more suitable rather than the generated heat. However, nanoparticles' temperature changes are both directly and indirectly effected by many environmental factors, impeding an accurate performance testing. Therefore, evaluations through generated heat, instead of particle temperature should provide more accurate data on system performance. In this work, a single Fe3O4 nanoparticle is electromagnetically heated by a 12.6 mT 150 kHz field for 60 min at COMSOL Multiphysics. Time average of total heat generation by a single nanoparticle was found to be 2.43 x 10(-41) Wm(3). Fe3O4 is preferred due to its great electromagnetic characteristic and widespread use in drug formula Ferumoxytol. Small size of the nanoparticles creates a significant meshing challenge in numerical simulations, resulting in unfeasible computation times when using multiple particles. Accordingly, single particle simulation results were used to theoretically calculate heat generation capacity of 1 ml of Ferumoxytol as 2.62 x 10(-18) Wm(3). Combining simulations with theoretical calculations proved to be effective in creating a basis for future studies towards; minimizing total simulation time, computer power and optimizing input waveforms for magnetic hyperthermia systems.