Filtern
Dokumenttyp
- Vortrag (26)
Referierte Publikation
- nein (26)
Schlagworte
- DNA (18)
- Geant4 (17)
- Dosimetry (14)
- Geant4-DNA (12)
- Radiation damage (10)
- MCS (9)
- Microdosimetry (9)
- LEE (6)
- Proteins (6)
- G5P (5)
- Ionizing radiation (5)
- Protein (5)
- TOPAS (5)
- Hydroxyl radical (4)
- Low energy electrons (4)
- Monte-Carlo simulations (4)
- Particle scattering simulation (4)
- Particle scattering simulations (4)
- Topas (4)
- XPS (4)
- Base damage (3)
- Base loss (3)
- Cancer therapy (3)
- Hydroxyl radicals (3)
- NAP-XPS (3)
- Near ambient pressure xray photo electron spectroscopy (3)
- OH radical (3)
- Prehydrated electron (3)
- ROS (3)
- Radiation therapy (3)
- Reactive oxygen species (3)
- Simulation (3)
- Xray photo electron spectrocopy (3)
- Analytic (2)
- Cancer treatment (2)
- Certification (2)
- DNA radiation damage (2)
- DSB (2)
- Desintegracion radioactiva (2)
- Direct damage (2)
- Dissociative electron attachment (DEA) (2)
- Dissociative electron transfer (DET) (2)
- Dosimetrie (2)
- ESCA (2)
- Ectoine (2)
- Electrons (2)
- Homogeneity (2)
- Hydrated DNA (2)
- Hydrated electron (2)
- Hydration shell (2)
- Indirect damage (2)
- Ionization (2)
- Monte-Carlo Simulations (2)
- Monte-Carlo simulation (2)
- Método de Montecarlo (2)
- Net-ionization reaction (2)
- PES (2)
- Prehydrated electrons (2)
- Quality testing (2)
- Quasi-direct damage (2)
- Radiation (2)
- Radical (2)
- Radioactive decay (2)
- Radioactive nanoparticle (2)
- Raman (2)
- Reference material (2)
- Referenzmaterialien (2)
- SSB (2)
- Scattering (2)
- Simulations (2)
- Single-strand break (SSB) (2)
- Single-stranded DNA-binding proteins (2)
- Stability (2)
- TOPAS-nBio (2)
- TOPAS-nbio (2)
- Xray (2)
- nanoparticula (2)
- Absorbed dose (1)
- Analysis (1)
- AuNP (1)
- Biopolymers (1)
- C++ (1)
- Cancer (1)
- Cmake (1)
- Compatible solutes (1)
- Computer simulation (1)
- Computertomographie (1)
- Curve fitting (1)
- DEA (1)
- DET (1)
- DNA strand break (1)
- Debian (1)
- Dose (1)
- Double strand breaks (1)
- Double-strand break (1)
- Double-strand break (DSB) (1)
- Dry DNA (1)
- ESEM (1)
- Ectoine radiation protection (1)
- Effective dose (1)
- Electrohpresis (1)
- Electron irradiation (1)
- Electron scattering (1)
- Energiedosis (1)
- Energy deposit (1)
- Energy dose (1)
- Equivalent dose (1)
- Fityk (1)
- Functionalization (1)
- GVP (1)
- Git (1)
- IR (1)
- IRPA (1)
- Ionisation (1)
- LET (1)
- LLG (1)
- Linear energy transfer (1)
- Linux (1)
- MPL (1)
- Magnetic nanoparticle (1)
- Magnetism (1)
- Medizintechnik (1)
- Micromagnetism (1)
- Monte Carlo (1)
- Monte carlo simulations (1)
- Monte-Carlo Simulation (1)
- Monte-Carlo Simulationen (1)
- Nanoparticle (1)
- Nanostructuring (1)
- OH (1)
- OH radicals (1)
- OOMMF (1)
- Particle scattering (1)
- Phantome (1)
- Pharmacy (1)
- Plasmid DNA (1)
- Polymer (1)
- Polymer degradation (1)
- Polymers (1)
- Presolvated electron (1)
- Radiadion damage (1)
- Radiation damage to DNA (1)
- Radiation protection (1)
- Radioactive NP (1)
- Radiolysis (1)
- Radiotherapy (1)
- SEM (1)
- Salt (1)
- Scavenger (1)
- Sensing (1)
- Single strand breaks (1)
- Single-strand break (1)
- Strahlentherapie (1)
- Strand breaks (1)
- Topas-nbio (1)
- Water (1)
- Xrays (1)
- dosimetry (1)
- geant4 (1)
- gold nanoparticles (1)
- low energy electrons (1)
- radiation Damage (1)
- radicals (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (26) (entfernen)
Radiation biophysics
(2023)
X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further. Furthermore, first data about the degradation of single-stranded DNA binding-proteins (G5P / GV5 and hmtSSB) under vacuum and NAP-XPS conditions are presented.
We give an overview about recent work concerning ionizing radiation damage to Oligonucleotides, plasmid DNA, DNA binding proteins (G5P), and DNA-protein complexes.
We focus on combining new experimental setups with Geant4/TOPAS particle scattering simulations to understand the effets of ionizing radiation.
Radiation damage to DNA is one of the main causes for cancer and likewise a major tool in its treatment. One of the dogma of the classical radiochemistry and physics involves the opinion that radicals such as OH° produced by ionizing radiation are the most lethal agents. This scenario is increasingly disputed as secondary low-energy electrons are emerging [1] as important, if not predominant, reductive pathway in ionizing damage of biomolecules. These electrons are generated in copious amount in aqueous environment as secondary scattering products. But until now all research concerning the quantification of the effects of low energy electrons on the biomolecular damage was either performed in vacuum with low energy electron sources or with DNA plasmids on metallic surfaces in humid environment. In this work we present detailed experimental and simulation microdosimetry data on electron damage to plasmid DNA in liquid environment: Well-defined electron energy and dosage irradiation was achieve by using an EM and the irradiation through a nanomembrane. The results are analyzed in terms of single- and double-strand break probabilities in the dependence of dose, energy, number of primary and secondary electrons. The results are important not only from the basic scientific point of view but also for the development of effective radiosensitizers, either as protecting or enhancing (radiotherapy) cofactors.
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.
Reference Materials at BAM
(2021)