Assessment of a cluster of gold nanoparticles effect on cell absorbed dose using the Geant4 toolkit

Introduction: Radiotherapy plays a vital role in cancer treatment. To establish a new potency in radiosensitize tumor cells, delivery of High-Z materials is offered. To date, several simulation geometries have been applied to define simulation sets. The clustering of nanoparticles (NPs) within the cells is a prominent parameter usually ignored in simulation studies. Materials and Methods: The simplified geometry of the cell was simulated. The modeled nucleus was a cube of 13 ×10×5 µm3 corresponding to the box of the nucleus in WholeNuclearDNA which was filled with liquid water. Nanoparticles were arranged in an orderly manner next to the box of modeled nucleus. To define the impacts of different energies and sources on dose enhancement ratio (DER) in the target, mono-energetic photon and electron beams within keV to MeV range spread spatially from a source point. Also, this proposed model was to assess the optimum features of GNPs structure parameters, like the size. Results: The largest volumes of DER of photons were about 40 and 108 fold in the nucleus and cytoplasm when GNPs were consumed, and the same was 2.4 and 1.12 for electron beams in cellular regions, respectively. It was demonstrated that the linear correlation between DER and GNPs size was for 40 keV photons, while there was no striking change for 900 keV electron beam when GNPs size changes. Conclusion: It is concluded that GNPs in combination with the electron beams are less efficient compared to the low energy photons. Larger GNPs do not show any preference when irradiated through electron beams as much as they do with photons.