| Zugriffsnummer | 25552 |
| Dokumenttyp | Konferenzartikel in Zeitschrift |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Nanodosimetry: bridging the gap to radiation biophysics [invited talk] |
| Autor(in); Institution |
Rabus, Hans; 6.6, Grundlagen der Dosimetrie, PTB-Braunschweig
Nettelbeck, Heidi; 6.6, Grundlagen der Dosimetrie, PTB-Braunschweig
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| Quelle/Jahr | Proceedings of the 16th Solid State Dosimetry Conference, September 19 - 24, Sydney, Australia. Radiation Measurements: 46 (2011), 12, 1522 - 1528 |
| ISSN | 1350-4487 |
| DOI | |
| Verlag | Oxford: Elsevier |
| Konferenzangaben | 16th International Conference on Solid State Dosimetry (SSD), Sydney, 19-24, September, 2010, Australia |
| Freie Schlagworte | Nanodosimetry ; Radiation biology ; Monte Carlo track structure ; Cluster size distributions ; DNA damage |
| Zusammenfassung | Introduction: Radiation induced damage to biological cells is predominately initiated by inelastic interactions of the ionising particle or its secondary electrons with the DNA molecule or surrounding water molecules. The sub-cellular distribution of such interactions therefore plays a key role in the biological effectiveness of ionising radiation. Hence, the definition of concepts like radiation quality should more appropriately be better based on quantities derived from the details of particle track structure on a nanometre scale. An overview of recent developments in the field of nanodosimetry working towards this goal will be presented. Methods: Nanodosimetry aims to establish a concept of radiation quality building on the measurable track structure properties of ionising radiation. Experimental and numerical techniques have been developed to characterise the particle track structure based on the formation of ionisation clusters within a specified target volume comparable in mass per unit area to a DNA segment. The probability distribution of the number of ionisations produced by a passing primary particle and its secondaries is characteristic of radiation quality. Ionisation cluster size distributions in macroscopic gaseous targets have been measured by means of an ion counting nanodosimeter developed by the Weizmann Institute of Science in collaboration with the PTB [Garty 2002]. Complementary Monte Carlo simulations of ionisation cluster formation in nanometric volumes of condensed matter have also been performed by means of the PTB track structure code. This code was developed to allow step-by-step simulation of secondary electrons down to the ionization threshold. Such low-energy electrons are of interest as their high LETs make them significant contributors to radiation damage. A theoretical scaling relation can be used to relate equivalent combinations of target volume, material and density that produce comparable ionisation cluster size distributions [Großwendt 2004]. Results: Measurements with the nanodosimeter have verified the applicability of the scaling procedure for ionisation cluster size distributions in different gases and validated the PTB track structure code. As shown in Figure 1, a comparison of these measurements with radiobiological data suggests a correlation between the probability for initial DNA damage and the moments of ionisation cluster size distributions in nanometric water cylinders or equivalent nitrogen-filled targets in the nanodosimeter. An upgrade of the PTB Monte Carlo code to include cross section data of DNA constituents is in progress. The cross sections for the interaction of low energetic electrons with biomolecules, which are used as a substitute for the building blocks of DNA, have been determined experimentally. Preliminary results for ionisation cluster formation based on these cross section data will be presented at the conference. Monte Carlo simulations are also in progress to supplement current radiobiological experiments investigating the influence of a magnetic field on chromosomal aberrations in lymphocytes and the use of nanoparticles to enhance the radiation damage to DNA. Details of this research will be also presented at the conference. Conclusions: Nanodosimetry is an emerging technology which can be used to estimate radiobiological effects for particular biological endpoints. Measurements in macroscopic gaseous targets have been used to validate the scaling procedure for ionisation cluster size distributions in different gases. Monte Carlo simulation has supplemented these measurements by enabling determination of corresponding distributions in nanometric volumes of condensed matter and a detailed study of the track structure of individual particles. Such simulations can be used to better understand radiation quality in terms of ionisation cluster formation. Corrigendum: Radiation Measurements: 47 (2012), 3, 241 After publication of the manuscript entitled "Nanodosimetry: Bridging the Gap to Radiation Biophysics" an error was found on page 1527. In the text, it is stated that the mass density for tetrahydrofuran (THF) was assumed to be 0.85 g/cm³ for simulations of ionisation cluster size distributions in a cylindrical target of size equivalent to a short DNA segment of 10 base pairs In fact, simulations have been carried out for two different values of the THF mass density, and the results shown in figure 6 were obtained for a THF mass density of 1.00 g/cm³. The figure below shows a comparison of the correct results for a THF mass density of 0.85 g/cm.sup3 and the data shown in figure 6. Compared to the results for a water-filled target, a THF-filled target of 1.00 g/cm³ density deviates by about 40% whilst for a THF target of 0.85 g/cm³ density the deviation is almost a factor of two. |
| Relation |
https://doi.org/10.1016/j.radmeas.2012.01.004 – (Corrigendum (2012))
https://doi.org/10.1016/j.radmeas.2026.107731 – (Corrigendum (2026))
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