Photoelectronic Processes when Irradiating Magnetite Nanoparticle with a Monochromatic X-Ray Beam.

The possibility of applying magnetite nanoparticles for the purpose of improving the efficiency of cancer-tumor suppression during X-ray brachytherapy treatment is considered. The proposed role of the nanoparticles is to enhance the dose of ionizing radiation, absorbed by the tumor, into which the injection of solution containing such particles is carried out. These particles possess several properties that make them useful for the targeted delivery of radiation to tumors. Magnetite nanoparticles are biodegradable and magnetic and can emit secondary radiation when irradiated with an external source. In this work, the dose distribution around a magnetite particle 10 nm in diameter, immersed into water and irradiated by monochromatic X-rays with energies in the range from 4 to 60 keV is calculated. In this case, water can be considered as a good enough equivalent of biological tissue for model computations. Using Monte Carlo computations with the Geant4 program package, it is shown that under such conditions, an increase in the dose absorbed by water on account of the generation of X-ray fluorescence radiation really takes place; however the spatial region, where such enhancement is rather high, is quite small. To apply the method effectively, one would need to deliver such nanoparticles directly into the cell nucleus. [ABSTRACT FROM AUTHOR]