Wall-less Ion-counting Nanodosimetry Applied to Protons

Garty, Guy; Shchemelinin, S.; Breskin, A.; Chechik, R.; Orion, Itzhak; Guedes, G. P.; Schulte, Robert; Bashkirov, V.; Großwendt, B.

doi:10.1093/oxfordjournals.rpd.a006794

Cited by 24 publications

(18 citation statements)

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“…With the help of such energy-dependent descriptions of nanodosimetric quantities like M 1 , a basis is created for a fast calculation of track structure properties. The ionisation cluster size distributions and the associated statistical parameters are measurable quantities [23][24][25][26][27] and could in the future − when practical instruments have been developed − be used in the clinic to characterise track structure and radiation quality of the treatment beam. In combination with a model predicting the radiobiological outcome − for example the RMF model that is linking double-strand break induction to reproductive cell death [28,29] − these parametrisations can be useful to achieve a higher accuracy for biological optimisation of treatment plans.…”

Section: Discussionmentioning

confidence: 99%

Energy dependent track structure parametrisations for protons and carbon ions based on nanometric simulations

et al. 2015

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Abstract. The BioQuaRT project within the European Metrology Research Programme aims at correlating ion track structure characteristics with the biological effects of radiation and develops measurement and simulation techniques for determining ion track structure on different length scales from about 2 nm to about 10 µm. Within this framework, we investigate methods to translate track-structure quantities derived on a nanometre scale to macroscopic dimensions. Input data sets were generated by simulations of ion tracks of protons and carbon ions in liquid water using the Geant 4 Monte Carlo toolkit with the Geant4-DNA processes. Based on the energy transfer points − recorded with nanometre resolution − we investigated parametrisations of overall properties of ion track structure. Three different track structure parametrisations have been developed using the distances to the 10 next neighbouring ionisations, the radial energy distribution and ionisation cluster size distributions. These parametrisations of nanometric track structure build a basis for deriving biologically relevant mean values which are essential in the clinical situation where each voxel is exposed to a mixed radiation field.

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Section: Discussionmentioning

confidence: 99%

Energy dependent track structure parametrisations for protons and carbon ions based on nanometric simulations

et al. 2015

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“…The measurement procedure for detecting ionisation clusters in diluted gases in coincidence with the original primary particles [8,9] and the development of dedicated Monte Carlo codes for complete particle track structure simulation are the two pillars on which nanodosimetry is based.…”

Section: Introductionmentioning

confidence: 99%

Secondary ionisations in a wall-less ion-counting nanodosimeter: quantitative analysis and the effect on the comparison of measured and simulated track structure parameters in nanometric volumes

et al. 2015

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Abstract. The object of investigation in nanodosimetry is the physical characteristics of the microscopic structure of ionising particle tracks, i.e. the sequence of the interaction types and interaction sites of a primary particle and all its secondaries, which reflects the stochastic nature of the radiation interaction. In view of the upcoming radiation therapy with protons and carbon ions, the ionisation structure of the ion track is of particular interest. Owing to limitations in current detector technology, the only way to determine the ionisation cluster size distribution in a DNA segment is to simulate the particle track structure in condensed matter. This is done using dedicated computer programs based on Monte Carlo procedures simulating the interaction of the primary ions with the target. Hence, there is a need to benchmark these computer codes using suitable experimental data. Ionisation cluster size distributions produced in the nanodosimeter's sensitive volume by monoenergetic protons and alpha particles (with energies between 0.1 MeV and 20 MeV) were measured at the PTB ion accelerator facilities. C3H8 and N2 were alternately used as the working gas. (2013)]. Measured and simulated characteristics of the particle track structure are generally in good agreement for protons over the entire energy range investigated. For alpha particles with energies higher than the Bragg peak energy, a good agreement can also be seen, whereas for energies lower than the Bragg peak energy differences of as much as 25% occur. Significant deviations are only observed for large ionisation cluster sizes. These deviations can be explained by a background consisting of secondary ions. These ions are produced in the region downstream of the extraction aperture by electrons with a kinetic energy of about 2.5 keV, which are themselves released by ions of the "primary" ionisation cluster hitting an electrode in the ion transport system. Including this background of secondary ions in the simulated cluster size distributions leads to a significantly better agreement between measured and simulated data, especially for large ionisation clusters.

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“…The StarTrack Counter at INFN detects electrons generated in a sensitive volume of propane equivalent to a 20 nm biological target intersected by the primary particle track at a defined distance from the target centre [19,20]. The PTB Ion Counter also detects positive ions produced in a gas target corresponding to a target of about 2 nm in diameter [21,22].…”

Section: Nanodosimetrymentioning

confidence: 99%

Biologically Weighted Quantities in Radiotherapy: an EMRP Joint Research Project

Rabus

Hilgers

Sharpe

et al. 2014

EPJ Web of Conferences

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Abstract. Funded within the European Metrology Research Programme (EMRP) [1], the joint research project "Biologically weighted quantities in radiotherapy" (BioQuaRT) [2] aims to develop measurement and simulation techniques for determining the physical properties of ionising particle tracks on different length scales (about 2 nm to 10 μm), and to investigate the correlation of these track structure characteristics with the biological effects of radiation at the cellular level. Work package 1 develops micro-calorimeter prototypes for the direct measurement of lineal energy and will characterise their response for different ion beams by experiment and modelling. Work package 2 develops techniques to measure particle track structure on different length scales in the nanometre range as well as a measurement device integrating a silicon microdosimeter and a nanodosimeter. Work package 3 investigates the indirect effects of radiation based on probes for quantifying particular radical and reactive oxygen species (ROS). Work package 4 focuses on the biological aspects of radiation damage and will produce data on initial DNA damage and late effects for radiotherapy beams of different qualities. Work package 5 provides evaluated data sets of DNA cross-sections and develops a multi-scale model to address microscopic and nanometric track structure properties. The project consortium includes three linked researchers holding so-called Researcher Excellence Grants, who carry out ancillary investigations such as developing and benchmarking a new biophysical model for induction of early radiation damage and developing methods for the translation of quantities derived from particle track structure to clinical applications in ion beam therapy.

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Wall-less Ion-counting Nanodosimetry Applied to Protons

Cited by 24 publications

References 0 publications

Energy dependent track structure parametrisations for protons and carbon ions based on nanometric simulations

Energy dependent track structure parametrisations for protons and carbon ions based on nanometric simulations

Secondary ionisations in a wall-less ion-counting nanodosimeter: quantitative analysis and the effect on the comparison of measured and simulated track structure parameters in nanometric volumes

Biologically Weighted Quantities in Radiotherapy: an EMRP Joint Research Project

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