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Session: Therapy General ePoster Viewing [Return to Session]

Dose Enhancement Effects of High-Z Nanoparticles in Proton Therapy

K Duke, S Ahmad, A Lau, University of Oklahoma Health Sciences Center, Oklahoma City, OK


PO-GePV-T-70 (Sunday, 7/25/2021)   [Eastern Time (GMT-4)]

Purpose: To study using Monte Carlo simulation techniques the dose enhancement due to gold foils in energetic proton beam irradiation. The presence of high-Z nanoparticles has been recently studied for their ability to increase the number of secondary electrons thus enhancing dose to the target and shifting the Bragg peak location towards proximal depth. This Monte Carlo study compares the dose of a custom water phantom with gold foils to that of a control water phantom.

Methods: Two water phantoms of 30cmx30cmx40cm were created using the Topas 3.6.1 toolkit. The control phantom consisted of pure water and the custom phantom consisted of a 0.4 mm wide gold foil in water. The location of the foil was in the proximal to distal 80% Bragg Peak width of a 226 MeV proton beam with spot size of 2.7 mm diameter. Dose was scored in 0.1 mm resolution. The dose enhancement factor (DEF) as well as the shift in the Bragg Peak were quantized. Modular physics list which include g4em-standard_opt3, g4h-phy_QGSP_BIC_HP, g4decay, g4ion-binarycascade, g4h-elastic_HP and g4stopping were used. 5 million histories for DEF, and 0.2 million for the Bragg Peak shift were used.

Results: The introduction of gold foils in water phantom shifted the Bragg peak upstream by about 6 mm, and narrowed the peak from 8.1 to 3.1 mm. Our DEF findings showed an increase in enhancement as high as 1.46 situated around the Bragg Peak.

Conclusion: In this study, we simulated gold nano-particles placed in a foil with a proton beam. Our results showed a dose enhancement effect as well as a Bragg Peak shift. This preliminary study validates our simulation environment for future investigations. Future work will include simulation with many beam energies using different densities of gold nano-foils and other foils of different materials.



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