ИСТИНА

Magnetic hyperthermia using nanoparticles (MNP) is a clinically proven method of cancer treatment. MNPs could also be a promising target for combining hyperthermia with radiosensitization of the tumor. However, such applications of MNPs are poorly understood, and it is unclear what particle compositions can be relied upon. Therefore, the present work focuses on the search for materials that combine alternating magnetic field induced heating and the ability to increase the radiation dose associated with high atomic number. A theoretical evaluation of 24 promising compositions was carried out: values of the dose enhancement factor (DEF) for kilovoltage X-ray spectra were determined, and values of the specific absorption rate (SAR) were calculated for various combinations of elemental composition and particle size distribution. For alternating magnetic fields with an amplitude of 75–200 Oe and a frequency of 100 kHz, the maximum SAR values obtained ranged from 0.35 to 6000 W/g, and the DEF values for the studied compounds ranged from 1.07 to 1.59. Increasing the monodispersity of the MNPs led to an increase in SAR, which confirms the known experimental data. Four types of SAR dependences on the external magnetic field amplitude and the anisotropy constant were found for particles of different sizes. The most predictable SAR behavior corresponds to larger MNPs (~70-100 nm). Thus, based on these calculations, the following compositions La0.75Sr0.25MnO3, Gd5Si4, SmCo5, and Fe50Rh50 are the most promising for combining magnetic hyperthermia with radiation therapy. The greatest increase in dose is expected for surface radiotherapy.