Enhanced Radiosensitization Using Tio2 and Hfo2 Nanoparticles in Gamma Knife Radiosurgery: Insights From Geant4 and Geant4-Dna Simulations Publisher



Soleymani M ; Banaee N ; Nedaie H A ; Moghadam S R ; Mahdavi S R
Source: Physica Scripta Published:2026

Abstract

This study employs GEANT4 and GEANT4-DNA Monte Carlo simulations to evaluate the radiosensitization effects of titanium dioxide (TiO2) and hafnium dioxide (HfO2) nanoparticles (NPs) in Gamma Knife ICON radiosurgery. A multi scale simulation was performed to calculate dose enhancement factor (DEF) as well as DNA damage enhancement factor (DDEF) due to the presence of 20, 53, and 106 mg ml−1 TiO2 and HfO2 NPs with a size of 30, 65, or 100 nm. Increasing NP concentration and size resulted in higher DEF and DDEF, with HfO2 outperforming TiO2 due to its higher density and effective atomic number. Increasing NP concentration from 20 to 106 mg ml−1 raised the DEF by up to 10.5% for HfO2 and 6.82% for TiO2, while increasing NP diameter from 30 to 100 nm resulted in DEF increases of up to 3.10% and 2.10%, respectively. DNA damage yields (single- and double-strand breaks) followed similar trends, corroborating the enhanced radiobiological impact. Cell survival curves (obtained by Two-Lesion Kinetic model) demonstrated increased radiosensitization with higher NP concentration and size, particularly for HfO2. These findings suggest that HfO2 NPs represent a promising high-Z sensitizer for enhancing therapeutic efficacy in radiosurgery, warranting further comparative studies against established sensitizers such as gold. © 2026 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the IOP-Standard License.