Simulating Evaluation Method on Heating Performances of Magnetic Nanoparticles with Temperature-Dependent Heating Efficiencies in Tumor Hyperthermia

Abstract

The magnetic nanoparticles (MNPs) with decreasing heating efficiency (characterized by specific loss power, SLP) with temperature increase, especially around the Curie temperature (TC), are expected to realize the self-regulated temperature hyperthermia of the tumor. However, the actual decrease of the SLP is gradual, resulting in the deviation of self-regulated temperatures from the measured TC. So far, no method is available for evaluating the heating performances of those MNPs. Here, by simulating the temperature-dependent SLP, the heating performances of MNPs are evaluated from three clinically concerning aspects: The capacity for effective heating, the temperature uniformity in the tumor, and the temperature stability under environmental changes such as MNP loss or tumor progression. The developed methods were applied to ZnCoCrFeO, Fe3O4, and g-Fe2O3 MNPs. It was found that the uniform temperature distribution relies on lowering the heating power in the inner regions of the tumor, and the stable control of temperature depends on the dynamic adaptation of the heating power to the tumor temperature change. The proposed method may be used to predict the heating ability of MNPs and help the selection of MNPs for hyperthermia.