Fifty-seventh annual meeting of the American association of physicists in medicine
SU-E-T-518: Investigation of Gold Nanoparticle Radiosensitization for Carbon Ion Therapy
The aim of this work is to investigate the radiosensitization effect of gold nanoparticles (GNP) in carbon ion irradiation. Nano-scale dosimetric characteristics of GNP interaction with carbon ions as well as the secondary particles generated as a carbon beam traverses the water phantom were studied.
Monte Carlo simulations were carried out using TOPAS (Tool for Particle Simulation). First, a water phantom was irradiated by the carbon ion beam and the particle shower spectrum at several depths was recorded in phase spaces. We analyzed the number and energy spectrum of each particle type. Then, the phase spaces obtained from Step 1 were modified to nanometer scale to irradiate a single 50 nm GNP. The secondary electrons that escaped from the GNPs following interactions with each particle type were recorded as phase spaces. The number and energy spectrum of the secondary electrons were studied. The same simulations were repeated replacing the GNPs with water nanoparticles (WNPs) with the same size. The energy absorbed in either GNP or WNP was scored.
There is a large amount of secondary particles generated through carbon ion beam interaction with the water phantom. Analysis of the secondary electrons generated by the primary particles which escape from the nanoparticle revealed that majority (above 80%) of these electrons were generated by the GNP interaction with Carbon beam itself, making it the biggest contributor to the enhancement. The ratio of the energy absorbed by GNP and WNP is about 8–10 for charged particles and above 3000 for gammas.
We showed in the study the GNPs may potentially be used to enhance carbon ion therapy, and the main mechanism of enhancement is the interaction with Carbon ion particles itself.