The performance of a novel ion-counting nanodosimeter

Garty, Guy; Shchemelinin, S.; Breskin, A.; Chechik, R.; Assaf, Gad; Orion, Itzhak; Bashkirov, V.; Schulte, R.; Großwendt, B.

doi:10.1016/s0168-9002(02)01278-0

Cited by 83 publications

(103 citation statements)

References 21 publications

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“…1 shows a detailed view of the ion-counting nanodosimeter, currently in operation at the Weizmann Institute of Science and at Loma Linda University. The nanodosimeter and its performance are described in detail elsewhere [11]. The accelerator-generated primary particle beam traverses a low-pressure gas ionization volume (IV) and reaches a trigger detector (not shown).…”

Section: Experimental Nanodosimetry Nanodosimetric Site Conceptmentioning

confidence: 99%

“…The collimated ion beam enters and exits the ND via a thin (2.5 µm) Mylar window of 15 mm diameter. The beam localization and triggering system consists of a 2D-position sensitive multiwire proportional chamber (MWPC), followed by a 5 mm thick plastic scintillation detector, which is coupled to a photomultiplier tube (PMT) and collimated to 1 mm diameter [11]. The trigger and the offline analysis permit for an efficient pileup rejection [11].…”

Section: Performance Studies Experimental Setupmentioning

confidence: 99%

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Ion-counting nanodosimetry: current status and future applications

Schulte

Bashkirov

Garty

et al. 2003

Australas. Phys. Eng. Sci. Med.

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There is a growing interest in the study of interactions of ionizing radiation with condensed matter at the nanometer level. The motivation for this research is the hypothesis that the number of ionizations occurring within short segments of DNA-size subvolumes is a major factor determining the biological effectiveness of ionizing radiation. A novel dosimetry technique, called nanodosimetry, measures the spatial distribution of individual ionizations in an irradiated lowpressure gas model of DNA. The measurement of nanodosimetric event size spectra may enable improved characterization of radiation quality, with applications in proton and charged-particle therapy, radiation protection, and space research. We describe an ion-counting nanodosimeter developed for measuring radiation-induced ionization clusters in small, wall-less low-pressure gas volumes, simulating short DNA segments. It measures individual radiation-induced ions, deposited in 1 Torr propane within a tissue-equivalent cylindrical volume of 2-4 nm diameter and up to 100 nm length. We present ionization cluster size distributions obtained with 13.6 MeV protons, 4.25 MeV alpha particles and 24.8 MeV carbon nuclei in propane; they correspond to a wide LET range of 4-500 keV/micron. We are currently developing plasmid-based assays to characterize the local clustering of DNA damage with biological methods. Systematic comparison of biological and nanodosimetric data will help us to validate biophysical models predicting radiation quality based on nanodosimetric spectra. Possible applications for charged particle radiation therapy planning are discussed.

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Section: Experimental Nanodosimetry Nanodosimetric Site Conceptmentioning

confidence: 99%

Section: Performance Studies Experimental Setupmentioning

confidence: 99%

Ion-counting nanodosimetry: current status and future applications

Schulte

Bashkirov

Garty

et al. 2003

Australas. Phys. Eng. Sci. Med.

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“…It is likely that secondary electrons are the main contributor of additional clusters of smaller size (less than 10 ions), since the experimental and theoretical distributions excluding zero events agree very well in this range. Increasing discrepancy of the conditional cluster size distributions for >9 ions may be due to neutron contamination, since these would preferentially contribute large clusters, but could also be due to a rare ion multiplication mechanism in the ion acceleration channel below the ND aperture as suggested by Garty et al [2]. sizes larger than one ion with only small cluster sizes deriving from direct proton ionization within the SV.…”

Section: B Simulation Of Nanodosimetric Cluster Distributionsmentioning

confidence: 96%

“…The investigators at LLUMC, in collaboration with the Weizmann Institute of Science, have built and optimized two ion counting nanodosimeters [2,3].…”

Section: Experimental Nanodosimetrymentioning

confidence: 99%

“…As a consequence, the GEANT4 program provides the energy spectra and fluence distribution of the beam incident onto the ND as two separate output files. These output files are used as initial history input for a special Monte Carlo code that has been developed by Dr. Bernd Grosswendt at PTB to simulate the performance of the nanodosimeter [2].…”

Section: Experimental Nanodosimetrymentioning

confidence: 99%

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Nanodosimetric cluster size distributions of therapeutic proton beams

Wroe¹,

Schulte²,

Bashkirov³

et al.

IEEE Symposium Conference Record Nuclear Science 2004.

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Abstract-As we move into the new millennium, it is important that we improve our understanding of radiation effects on humans and nanoelectronic systems. This understanding is essential in a number of areas including radiation therapy for cancer treatment and extended human presence in outer space. Nanodosimetry in low-pressure gases enables measurement of the energy deposition of ionizing radiation on a scale equivalent to the dimensions of the DNA molecule. This is extremely important for not only biological applications but also electronic applications, as the effect of radiation on nanoelectronics needs to be determined before they are installed and deployed in complex radiation fields. However, before nanodosimetry can be widely applied, further investigation is required to link the output of gas-based nanodosimeters to the actual effect of the radiation on a biological or electronic system. The purpose of this research is to conduct nanodosimetric measurements of proton radiation fields at the proton accelerator of Loma Linda University Medical Center (LLUMC) and to develop a Monte Carlo simulation system to validate and support further developments of experimental nanodosimetry. To achieve this, measured ion cluster size distributions are compared to the output from the Monte Carlo simulation system that simulates the characteristics of the LLUMC beam line and the performance of the nanodosimeter installed on one of LLUMC's proton research beam lines.

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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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The performance of a novel ion-counting nanodosimeter

Cited by 83 publications

References 21 publications

Ion-counting nanodosimetry: current status and future applications

Ion-counting nanodosimetry: current status and future applications

Nanodosimetric cluster size distributions of therapeutic proton beams

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

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