Physical, Chemical and Biological Modelling for Gold Nanoparticle-Enhanced Radiation Therapy: Toward a Better Understanding and Optimization of the Radiosensitizing Effect
Speaker: Floriane Poignant
Date: Friday, Sept. 13, 2019 (New Date)
Time: 10:30 a.m.-11:30 a.m
Location: NIA, Room 219
Abstract:
In radiotherapy, the use of radiosensitizers aims at amplifying the destructive effects of the dose in the tumor. High-Z nanoparticles, such as gold nanoparticles (GNPs), have shown promising radiosensitizing properties that may originate from early physical and chemical mechanisms.
At an early stage, an increase in dose deposition and free radicals production throughout the tumor and at sub-cellular scale might be responsible for part of the effect for low-energy X-rays. While it has been studied for over a decade, the understanding of such effects remains under investigation. Theoretical tools such as Monte Carlo simulation (MCS) may help to better understand and quantify these early mechanisms and their impacts on cell survival.
At the Institut de Physique Nucléaire de Lyon (France), we developed event-by-event MCS to track secondary electrons down to low energy both in water and gold. In this presentation, the models implemented in the MCS will be briefly overviewed. The MCS was used to (1) quantify the energy deposited in nanotargets located near a GNP, which is correlated with the probability to generate sub-cellular damages. They were also used to (2) quantify the boost of free-radical production induced by GNPs at the cellular and sub-cellular scale. These chemical species are produced by the ionization and excitation of water molecules following an irradiation and are largely responsible for the toxicity of low-LET radiations. These two results were further used in the biophysical model NanOx, to (3) quantify the effect of GNPs in terms of cell death. This model was originally developed to predict cell death for ion irradiation in hadrontherapy. The effect of gold nanoparticles on these 3 quantities will be presented for irradiation with 20-90 keV photons and various nanoparticle sizes.
Bio:
Floriane Poignant obtained an engineering degree (the equivalent of a Master’s degree) at the Institut Mines-Telecom (IMT) Atlantique (Campus Mines de Nantes, France) in 2014, with a major in radiation physics and medical applications. In 2014, she did an internship at the University of Adelaide (Australia) in collaboration with the South Australian Health and Medical Research Institute (SAHMRI). She designed a simulation with the Monte Carlo tool Geant4 to model the solid target of the SAHMRI cyclotron and predict the production of radioisotopes used in nuclear medicine.
At the end of 2015, she joined the University of Lyon and the Nuclear Physics Institute of Lyon (France) to complete a Ph.D. degree, finishing at the end of September 2019. She worked on the modeling of early physical and chemical mechanisms to better understand the origin of the radiosensitizing properties of gold nanoparticles.