Experimental measurements validate the use of the binary encounter approximation model to accurately compute proton induced dose and radiolysis enhancement from gold nanoparticles.

Experimental measurements validate the use of the binary encounter approximation model to accurately compute proton induced dose and radiolysis enhancement from gold nanoparticles.
Phys Med Biol. 2019 Feb 07;:
Authors: Hespeels F, Lucas S, Tabarrant T, Scifoni E, Kraemer M, Chêne G, Strivay D, Tran HN, Heuskin AC
Abstract
In protontherapy, it has been suggested that nanoparticles of high-Z material like gold (GNP) be used as radiosensitizers. The origin of this enhancement phenomenon for proton radiation is not yet well understood and additional mechanistic insights are required. Previous works have highlighted the good capabilities of TRAX to reproduce secondary electron emission from gold material. Therefore, TRAX cross sections obtained with the binary encounter approximation (BEA) model for proton ionization were implemented within Geant4 for gold material.
 Based on the TRAX cross sections, improved Geant4 simulations have been developed to investigate the energy deposition and radical species production around a spherical gold nanoparticle (5 and 10 nm in diameter) placed in a water volume during proton irradiation. Simulations were performed for incident 2 MeV. The dose enhancement factor and the radiolysis enhancement factor were quantified. Results obtained with the BEA model were compared with results obtained with condensed-history models. 
 Experimental irradiation of 200 nm gold films were performed to v...

Source: Physics in Medicine and Biology - February 7, 2019 Category: Physics Authors: Hespeels F, Lucas S, Tabarrant T, Scifoni E, Kraemer M, Chêne G, Strivay D, Tran HN, Heuskin AC Tags: Phys Med Biol Source Type: research