A new method for measuring ion clusters produced by charged particles in nanometre track sections of DNA size

Pszona, S.; Kula, J.; Marjanska, S

doi:10.1016/s0168-9002(99)01191-2

Cited by 60 publications

(16 citation statements)

References 6 publications

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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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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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“…To date, three types of nanodosimeter have been developed that measure frequency distribution of ionisation cluster size in a gas, where the respective target volumes correspond to different sizes of nanometric targets in biological matter. The Jet Counter at NCBJ detects positive ions produced by primary particles passing centrally through a pulse of nitrogen gas simulating biological target sizes of about 2 nm and 20 nm by adjusting the density of molecules [17,18]. 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].…”

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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“…[12][13][14][15][16] Therefore, a more suitable tool for track structure description may be nanodosimetry. 17 In nanodosimetry, [18][19][20][21][22][23][24][25] the track structure of charged particles is characterized by the frequency distributions of the ionization cluster size (ICS), that is, the number of ionizations produced within a target volume in nanoscale. Direct measurements of the distributions can be conducted using nanodosimeters, while only limited number of nanodosimeters under restricted measurement conditions are working now.…”

Section: Introductionmentioning

confidence: 99%

Nanodosimetric quantities and RBE of a clinically relevant carbon‐ion beam

Dai

Liu

et al. 2019

Medical Physics

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Purpose Although carbon‐ion therapy is becoming increasingly attractive to the treatment of tumors, details about the ionization pattern formed by therapeutic carbon‐ion beam in tissue have not been fully investigated. In this work, systematic calculations for the nanodosimetric quantities and relative biological effectiveness (RBE) of a clinically relevant carbon‐ion beam were studied for the first time. Methods The method combining both track structure and condensed history Monte Carlo (MC) simulations was adopted to calculate the nanodosimetric quantities. Fragments and energy spectra at different positions of the radiation field of a clinically relevant carbon‐ion pencil beam were generated by means of MC simulations in water. Nanodosimetric quantities such as mean ionization cluster size (M1), the first moment of conditional cluster size (M1C2), cumulative probability (F2), and conditional cumulative probability (F3C2) at these positions were then acquired based on the spectra and the pre‐calculated nanodosimetric database created by track structure MC simulations. What’s more, a novel approach to calculate RBE based on the said nanodosimetric quantities was introduced. The RBE calculations were then conducted for the carbon‐ion beam at different water‐equivalent depths. Results Lateral distributions at various water‐equivalent depths of both the nanodosimetric quantities and RBE values were obtained. The values of M1, M1C2, F2, and F3C2 were 1.49, 2.67, 0.30, and 0.38 at the plateau at the beam central axis and maximized at 2.79, 5.69, 0.47, and 0.68 at the depths around the Bragg peak, respectively. At a given depth, M1 and F2 decreased laterally with increasing the distance to the beam central axis while M1C2 and F3C2 remained nearly unchanged at first and then decreased except for M1C2 at the rising edge of the Bragg peak. The calculated RBE values were 1.07 at the plateau and 3.13 around the Bragg peak. Good agreement between the calculated RBE values and experimental data was obtained. Conclusions Different nanodosimetric quantities feature the track structure of therapeutic carbon‐ion beam in different manners. Detailed ionization patterns generated by carbon‐ion beam could be characterized by nanodosimetric quantities. Moreover the combined method adopted in this work to calculate nanodosimetric quantities is not only valid but also convenient. Nanodosimetric quantities are significantly helpful for the RBE calculations in carbon‐ion therapy.

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A new method for measuring ion clusters produced by charged particles in nanometre track sections of DNA size

Cited by 60 publications

References 6 publications

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

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

Nanodosimetric quantities and RBE of a clinically relevant carbon‐ion beam

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