Solution to the bioheat equation for hyperthermia with La_1−xAg_yMnO_3-δ nanoparticles: The effect of temperature autostabilization

Abstract

This work aimed to analyze the possibility and performance of the temperature controlled hyperthermia based on AC heating of magnetic nanoparticles with low Curie temperature. Temperature dependence of dynamic magnetic susceptibility has been studied experimentally on fine powders of La_0.8Ag_0.15MnO_2.95 in the frequency range of 0.5–2.0 MHz. Critical drop of the AC magnetic losses was found in the vicinity of the Curie point, T_C = 42°C. The obtained data was used in the numerical analysis of the bioheat equations under typical conditions of the hyperthermia treatment. The mathematical model includes a spherical tumor containing magnetic particles and surrounded by concentric healthy tissue, with account made for the blood perfusion. The calculations performed for various AC power, tumor sizes and doping geometries predict effective autostabilization of the temperature at T ≅ T_C inside the tumor and steep temperature profile at the interface with the healthy tissue.

• Radiofrequency
• magnetic particles
• manganites
• Curie temperature
• temperature stabilization