Application of magnetic hyperthermia in prostate cancer treatment.

PURPOSE: The aim of this study was to determine the required concentration of magnetic nanoparticles to achieve the therapeutic temperature in prostate cancer treatment during magnetic hyperthermia, taking into account the influence of the geometry of the heated region. In this context, four types of magnetic nanoparticles were considered in the calculations: maghemite, magnetite, cobalt ferrite, and barium ferrite. METHODS: An air coil generating an alternating magnetic field was designed to obtain a uniform magnetic field distribution in the prostate region. The magnetic field distribution was used to calculate the volumetric power density generated by the magnetic nanoparticles. Thermal simulations were conducted for a naturalistic prostate tumour and three geometric primitives (cylinder, sphere, and cube) placed in the same anatomical location for comparison purposes. To evaluate the concentration of various types of magnetic nanoparticles, the linear response theory was used. RESULTS: The concentrations of magnetic nanoparticles for the tumour, cylinder, sphere, and cube required to achieve the therapeutic temperature were determined. The results revealed noticeable differences between the tumour model and simplified geometries in terms of both required nanoparticle concentration and heating efficiency. CONCLUSIONS: The obtained results indicate that the concentration of magnetic nanoparticles required to achieve therapeutic temperatures strongly depends on the geometry of the heated region, type of magnetic nanoparticles, and their concentration. Furthermore, the use of simplified geometrical models may lead to significant inaccuracies in predicting heat generation, suggesting that realistic tumour geometry should be considered in magnetic hyperthermia studies. These findings highlight the necessity of individualized treatment planning.