TY - JOUR
A1 - Zutta Villate, J. M.
A1 - Hahn, Marc Benjamin
T1 - Radioactive gold nanoparticles for cancer treatment
JF - European Physical Journal D
N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour.
KW - Gold
KW - Nanoparticle
KW - Cancer
KW - Monte-Carlo
KW - Simulation
KW - Cluster
Y1 - 2019
U6 - http://dx.doi.org/10.1140/epjd/e2019-90707-x
VL - 73
IS - 95
SP - 1
EP - 7
ER -
TY - GEN
A1 - Hahn, Marc Benjamin
T1 - Geant4: A universal Monte-Carlo toolkit for Particle scattering simulations
N2 - Particle scattering simulations are an useful tool to plan experiments, design detectors, estimate doses in irradiated materials and medical treatment planning.
Geant4 is a Monte-Carlo toolkit for the simulation of of particles scattering in matter. Photons, electrons, ions etc can be simulated with energies in the eV to GeV range. Their interactions with matter in arbitrary scattering geometries be studied. Scattering models, cross sections and material parameters can be set to cover interactions in gas, liquid and solid state. The import of geometries from computer aided design files or the protein data base is possible.
It is currently being applied in high energy and nuclear physics, accelerator and detector design, space application, dosimetry and medical sciences.
In this first part of the talk a brief overview over the structure, functionality and possible applications of Geant4 will be given. In the second part an example application will be presented: The determination of the microscopic dose-damage relations in aqueous environment for electron irradiated plasmid DNA will be explained. Therefore, we combine electron scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We present, how to combine these simulational results and experimental data via a generalized damage model to determine the microscopic dose-damage relation at a molecular level.
KW - Geant4
KW - Dosimetry
KW - Microdosimetry
KW - Radiation damage
KW - Electron irradiation
KW - Monte-Carlo Simulation
KW - Monte-Carlo Simulations
KW - DNA
KW - Computer simulation
KW - Geant4-DNA
Y1 - 2019
ER -
TY - GEN
A1 - Hahn, Marc Benjamin
T1 - Measurement and Simulation of the Microscopic Energy Deposit:
A general approach applicable to Ionizing Radiation Sources of varying Linear Energy Transfer
N2 - The determination of microscopic dose-damage relations in aqueous environment is of fundamental interest for dosimetry and its application in radiation-therapy and protection. We present a combined experimental and simulational approach to quantify the microscopic energy deposit at biomolecules in liquid environment which is applicable to a wide range of primary radiation sources, e.g. photons, electrons or ions, and targets, such as DNA, proteins or cells.Therefore, we combine Geant4 particle-scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We present, how to combine these simulational results and experimental data via a generalised damage model to determine the microscopic dose-damage relation at a molecular level.
To show the viability of this approach, we apply this method to an experimentally challenging system, the direct irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here we combine electron-scattering simulations with calculations concerning the diffusion and convection induced movement of the DNA, within a coarse-grained model of the irradiated liquid. Additionally a microscopic target model for DNA molecules based on the relation of lineal energy and radiation quality is used to calculate their effective target volume.
It was found that on average fewer than two ionisations within a 7.5\,nm radius around the sugar-phosphate backbone are sufficient to cause a single strand break, with a corresponding median lethal energy deposit being E\textsubscript{1/2}=6+-4\,eV. The presented method is applicable for all types of ionising radiation and a broad variety of biological targets.
KW - Dosimetry
KW - Microdosimetry
KW - Geant4
KW - Geant4-DNA
KW - DNA
KW - Electron irradiation
KW - Monte-Carlo Simulation
Y1 - 2019
UR - https://www.bipm.org/utils/en/pdf/Workshop-CCQM2019-EP1.pdf
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Zutta Villate, Julian Mateo
T1 - Radioactive gold nanoparticles for cancer treatment: Size and cluster dependent damage studied by Geant4 Monte-Carlo simulations
JF - Topical Issue: Dynamics of Systems on the Nanoscale (2018)
N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive ¹⁹⁸Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply ¹⁹⁸AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour.
KW - Gold Nanoparticles
KW - AuNP
KW - Radioactive decay
KW - Beta decay
KW - DNA
KW - DNA damage
KW - Radiation damage
KW - MCS
KW - Monte-Carlo simulation
KW - Geant4
KW - Dosimetry
KW - Microdosimetry
KW - Cancer treatment
KW - Radiationtherapy
KW - Brachytherapy
KW - OH radicals
KW - LEE
KW - low energy electrons
KW - gamma ray
KW - beta particle
KW - radiolysis
KW - clustered nanoparticles
KW - NP
KW - Simulation
KW - particle scattering
KW - Geant4-DNA
KW - Energy deposit
Y1 - 2019
UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=CCC&DestLinkType=FullRecord&KeyUT=CCC:000467692900010
U6 - http://dx.doi.org/10.1140/epjd/e2019-90707-x
SN - 1434-6060
SN - 1434-6079
VL - 73
IS - 5
SP - 95, 1
EP - 7
PB - Springer
CY - Berlin Heidelberg
ER -
TY - GEN
A1 - Hahn, Marc Benjamin
T1 - Simulational tools in nanoparticle research: Micromagnetics and particle scattering
N2 - Simulational tools are applied to investigate the physical properties of nanoparticles.
For the description of radioactive gold nanoparticles, particles scattering simulations are performed with the Geant4 monte carlo simulation toolkit.
The temperature dependent behaviour of the magnetization dynamics of different magnetic nanoparticles are simulated with the object oriented micormagnetic framework (OOMMF).
KW - Monte Carlo
KW - Monte-Carlo simulation
KW - MCS
KW - Nanoparticle
KW - AuNP
KW - Dosimetry
KW - Radioactive NP
KW - Microdosimetry
KW - Geant4
KW - OOMMF
KW - Micromagnetism
KW - Simulation
KW - Magnetic nanoparticle
KW - LLG
Y1 - 2019
ER -