The possibility of application of magnetic core-shell Fe3O4/Ta2O5nanoparticles has been investigated in order to enhance the effect of radiation therapy. It has been shown, that an increase of the concentration of the core-shell nanoparticles due to the influence of the nonuniform magnetic field enhances the absorption of gamma quanta with energy destroying tumor cells (20-200 keV). In addition, an increase of nanoparticles concentration promotes the formation of electron-positron pairs, annihilation of which are leads to an increase in the number of secondary gamma quanta with an energy of 511 keV.

The effect of the tantalum, platinum and gold nanoparticles on the energy distribution of the high-energy photons in the tissue-equivalent media is studied. It was shown that the presence of nanoparticles results in emergence in the medium of the electron-positron pairs manifesting in the decrease in the number of the primary photons and emergence of the secondary photons with energies of 511 keV and lower.

Gamma spectrums were measured during X-ray transmission through solutions such as sodium chloride solution with increasing quintuple concentration of NaCl and cisplatin with increasing quintuple concentration of platinum. It was shown that the number of photons with an energy of 511 keV is 29.6% more in cisplatin solution with increasing quintuple concentration of platinum (5*cisplatin) than sodium chloride solution increasing quintuple concentration of NaCl. The result allows us to consider cisplatin as a possible radiomodificator for radiation therapy.