Radiosensitization with iron nanoparticles under 10–800 Ry photon irradiation: Monte Carlo simulation of particle-to-medium energy transfer

Abstract

The processes in 2–128 nm iron nanoparticles (NP) under 10–800 Ry photon irradiation are studied by detailed Monte Carlo simulations, accounting for the cascade decays of inner-shell vacancies. The cascade decay of vacancies is a crucial factor in the theoretical description of the effect of ionizing radiation on matter. The NPs re-emit most of the energy of an absorbed photon into the surrounding medium with secondary electrons and photons emitted by NP. At incident photon energies under the Fe1s-ionization threshold, most of the energy is carried away by electrons; when photon energy is above the Fe1s-threshold, electrons and photons transfer the energy to the surrounding medium. In the case of large nanoparticles, many low-energy electrons are emitted by NP, over a hundred per one initial photon. Although the energy carried away by them is small, they contribute to forming a high positive charge on the NP, which results in great electric fields near the NP surface. The significance of the NP electric field effect on the DNA repair cycle is discussed.

KEYWORDS:

• Radiotherapy
• radiosensitization
• iron nanoparticles
• cascade decay of inner-shell vacancies
• Monte Carlo simulation

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No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Alexander P. Chaynikov

Alexander P. Chaynikov is an associate professor of the department of Physics at Rostov State Transport University, Russia. He received master's degree in physics in 2014 in Southern Federal University, and received a PhD in condensed matter physics at Rostov State Transport University in 2018 for studying the role of cascade decays of inner-shell vacancies of ionized atoms in the ionizing radiation effect on matter. He is engaged in Monte Carlo simulation of the interaction of ionizing radiation with matter, including problems of radiosensitization using the introduction of high-Z atoms and nanoparticles. He co-authored about 30 scientific papers.

Andrei G. Kochur

Andrei G. Kochur is a head of the department of Physics at Rostov State Transport University, Russia. He received his PhD degree in 1982 in Rostov State University (presently Southern Federal University), and his Doctor of Physical-Mathematical Sciences degree in 1997 in Rostov State Transport University. The domain of his scientific activities includes x-ray and electron spectroscopy, electronic structure theory, theory of fundamental processes in atoms, spectroscopic methods in material science, physical methods in engineering, and ionizing radiation effect on matter. He co-authored more than 250 scientific papers.

Victor A. Yavna

Victor A. Yavna is a professor of the department of Physics at Rostov State Transport University, Russia. He received his PhD degree in 1982 in Rostov State University (presently Southern Federal University), and his Doctor of Physical-Mathematical Sciences degree in 1994 in Rostov State Transport University. His scientific interests include the physics of atoms and molecules, the interaction of electromagnetic radiation with matter, GPR, diagnostics of engineering structures using non-destructive testing methods. He co-authored more than 340 scientific papers.