Program Information
Evaluation of Dose Enhancement by Clustered and Non-Clustered Gold Nanoparticles
K Sutherland1*, J Kwon2 , A Makarova3 , T Matsuura4 , T Hashimoto5 , H Peng6 , K Umegaki7 , S Shimizu8 , M Ishikawa9 , H Shirato10 , (1) Hokkaido University, Sapporo, Hokkaido, (2) Hokkaido University, Sapporo, Hokkaido, (3) Hokkaido University, Sapporo, Hokkaido, (4) Hokkaido University, Sapporo, Hokkaido, (5) Hokkaido University, Sapporo, Hokkaido, (6) Stanford University, Stanford, CA, (7) Hokkaido University, Sapporo, Hokkaido, (8) Hokkaido University, Sapporo, Hokkaido, (9) Hokkaido University, Sapporo, Hokkaido, (10) Hokkaido University, Sapporo, Hokkaido
Presentations
TU-C2-GePD-T-3 (Tuesday, August 1, 2017) 10:00 AM - 10:30 AM Room: Therapy ePoster Lounge
Purpose: To evaluate the effect of the clustering of gold nanoparticles (GNPs) compared with homogenous distributions within a simulated cell.
Methods: Biological parameters reported by Peckys [Nano Letters, 11, 4, (2011)] were used to conduct Geant4 Monte Carlo simulations. A cluster of vesicles within a tumor cell was simulated by randomly distributing 164 spherical vesicles in a 4 μm cube of water, then randomly distributing GNPs within each vesicle. The diameter of each vesicle was 260 nm, the diameter of the GNPs was 10, 30 and 50 nm and the weight concentration of GNPs in the cell was 1 and 4 mg/mL. For comparison, a homogeneous distribution without clustering was made in a 12.6 μm cube cell phantom of water. The energy deposited in the surrounding water and absorbed by GNPs were calculated for each distribution under 100 keV X-ray irradiation to the cell phantom.
Results: For both 1 and 4 mg/mL GNPs concentration, the energy deposited by electrons within the GNPs increased with the GNP diameter. This suggests that the number concentration as well as the weight concentration of GNPs affect the dose enhancement because the number of smaller GNPs is much larger than that of bigger GNPs at the same weight concentration. Clustered GNPs absorbed significantly more dose than homogeneously distributed GNPs for all GNP diameters. The influence of the clustering was larger in 4 mg/mL concentrations than 1 mg/mL. The energy absorption by X-rays within the GNPs was insignificant in all cases.
Conclusion: The energy absorbed by GNPs increased as the weight concentration increases and the GNPs diameter decreases. Although the dose enhancement by GNPs is often reported with homogenous distributions, our results show the effect will be overestimated unless the absorption by clustered GNPs is taken into account.
Contact Email: