A novel approach to study radiation track structure with nanometer-equivalent resolution

Casiraghi, Margherita; Bashkirov, V.; Hurley, Ford; Schulte, R.

doi:10.1140/epjd/e2014-40841-0

Cited by 18 publications

(11 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At least two similar approaches have been developed independently by other groups [24], [25]. Furthermore, theoretical investigations suggest that biological radiation effects originate in the interaction of different DNA lesions [26].In consequence, respective new developments have been started in the field of experimental nanodosimetry that aim at measuring the correlations of cluster-size distributions induced within a particle track in two separate nanometric targets in proximity [27], [28] or at obtaining a 3D image of the nanometric particle track structure for track segments of few 100 nm in length [29], [30], [31]. The latter would to some extent bridge towards microdosimetric measurements at the few-hundred nanometer regime [12].…”

mentioning

confidence: 99%

Nanodosimetry – on the ''tracks'' of biological radiation effectiveness

Rabus¹

2020

Zeitschrift für Medizinische Physik

View full text Add to dashboard Cite

It is well known that the biological effectiveness of a certain absorbed dose of ionizing radiation depends on the radiation quality, i. e. the spectrum of ionizing particles and their energy distribution [1], [2], [3]. As has been shown in several studies, the biological effectiveness is related to the pattern of energy deposits on the microscopic scale, the socalled track structure [4]. Clusters of lesions in the DNA molecule within site sizes of few nanometers play a particular role in this context [4], [5], [6]. A first approach to measure track structure of ionizing radiation with nanometric resolution was proposed already in 1975 [7]. However, the extension of microdosimetric measurements to site sizes of few nanometer dimension was facing the fundamental problem that in such small sites the number of interactions is too low, such that the assumption fails that the imparted energy is the number of ionizations multiplied by a simple conversion factor [8]. Therefore, the development of methods for measuring track structure details with nanometric resolution required a change of paradigm, namely restricting the characterization of track structure to its ionization component [9], [10].In should be noted in this context that the term nanodosimetry is used in the literature in different meanings. These include ongoing endeavors to extend microdosimetry into the nanometer range to below 100 nm site sizes [11], [12] as well as simulation studies of various kinds that are not focused on quantities that are directly measurable. In this paper we use the term nanodosimetry for studies of charged particle track structure, considering the stochastics of ionizations in nanometric targets.The quantity of interest is the relative frequency distribution of the so-called ionization cluster size, i.e. the number of ionizations inside a considered target (often called the 'site'). As is illustrated in Figure 1, the ionization cluster size distribution (ICSD) varies with the geometrical position of the target with respect to the particle track. Furthermore, it also depends on the size and composition of the target and, most importantly, on the radiation quality. The ICSD can also be characterized by its statistical moments or the complementary cumulative frequencies of ionization clusters exceeding a certain minimum size [13].Around the turn of the century, three different types of nanodosimeters have been developed to measure the frequency distribution of ionization cluster size [14]. All devices are gas counters that simulate nanometric sensitive volumes based on a density scaling principle [15]. They Figure 1. Schematic illustration of nanodosimetric ionization cluster size (ICS) distributions in a spread-out Bragg peak (SOBP) of protons in water. The orange spheres indicate the loci of ionizing interactions of the proton or of the emitted secondary electrons. The blue and red cylinders represent nanometric targets located in the core and in the penumbra region of the track, respectively. The histograms with the blue and red...

show abstract

mentioning

confidence: 99%

Nanodosimetry – on the ''tracks'' of biological radiation effectiveness

Rabus¹

2020

Zeitschrift für Medizinische Physik

View full text Add to dashboard Cite

show abstract

“…Such a detector needs to be able to measure single ionizations over a large area with high resolution. One possible nanodosimetric detector which could be able to measure such cluster sizes along the primary particle track is the track imaging detector currently developed at University of Zurich and firstly suggested by Bashkirov et al 2,[27][28][29][30] The difference of the "fast" method and the "slow and detailed" method when the same Monte Carlo code is used presumably comes from excessive number of electrons in the "slow and detailed" method which ionize outside of the basic interaction volume where they were created. The "fast" method only takes the electrons into consideration which are generated and ionize inside the basic interaction volumes.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Feasibility study of macroscopic simulations of nanodosimetric parameters for proton therapy

et al. 2020

View full text Add to dashboard Cite

Purpose In view of the potential of treatment plan optimization based on nanodosimetric quantities, fast Monte Carlo methods for obtaining nanodosimetric quantities in macroscopic volumes are important. In this work, a “fast” method for obtaining nanodosimetric parameters from a clinical proton pencil beam in a macroscopic volume is compared with a slow and detailed method. Furthermore, the variations of these parameters, when obtained with the Monte Carlo codes TOPAS and NOREC, are investigated. Methods Monte Carlo track structure simulations of 1 keV–100 MeV protons and 12 eV–1 MeV electrons in a volume of 8 nm 3 liquid water provided us with an atlas of cluster size distributions. Two kinds of ionization cluster size distributions were recorded, counting all ionizations or only ionizations directly produced by the primary particle. The simulations of the proton pencil beam were performed in two different ways. A “fast” method where only the protons were simulated and a “slow and detailed” method where protons and electrons were simulated in order to obtain spectra at different depths. The obtained spectra were then convoluted with cluster size distributions. Results It was shown that the nanodosimetric quantity F2 from the “fast” method is, depending on the location, between 43.6% and 63.6% smaller than the F2 obtained by the “slow and detailed” method. However, it was also shown that variations of nanodosimetric quantities are even larger when the cluster size distributions of the electrons are simulated with the Monte Carlo code NOREC, that is, the cumulative F2 probabilities obtained with NOREC were between 50.8% and 75.5% smaller than the F2 probabilities obtained with TOPAS. Conclusions As long as the uncertainties of different Monte Carlo codes are not improved, it is feasible to only simulate protons in a macroscopic volume. It must be noted, however, that the uncertainty is in the order of 100%.

show abstract

“…The new device, developed starting from previous attempts of constructing a nanodosimeter small and simple enough to deploy [17][18][19], has the intriguing characteristic of being simple enough to be replicated in almost every physics laboratory, without the need for reproducing the relatively large facilities which have been employed since the beginning of this century for measuring the size distributions of ionization clusters produced by the interaction of ionizing radiation with atoms and molecules [20][21][22][23].…”

Section: Radiation Dosimetry With Laser-assisted Ionizationsmentioning

confidence: 99%

Quest for New Data: Ionizing Radiation Metrology in the Presence of Laser-Assisted Scattering Processes

Bianco¹,

Loffredo²,

Quarto³

et al. 2021

Photonics

View full text Add to dashboard Cite

Radiation metrology is crucial in space, for instance in monitoring the conditions on-board space vehicles. The energy released in matter by ionizing radiation is due to the atomic and molecular ionization processes, which have been investigated for several decades from both a theoretical and an experimental point of view. Electronic excitation and ionization cross-section are of particular interest in radiation physics, because of their role in the radiation–matter interaction process. Recently, experimental findings have shown that the interplay with a laser field can strongly modify the electronic interaction probabilities and emission spectra. These phenomena are still not completely understood from a theoretical point of view, and the available empirical data concern a few, simple atomic species. We represent a possible dosimetric effect of the interaction with laser light, inferring from experiments the characteristics of laser-assisted cross-sections. Using a Monte-Carlo calculation for simulating the micro-dosimetric aspects of the irradiation of a simple geometry, we show the need of new experimental data and more detailed theoretical approaches to these phenomena in complex molecular systems.

show abstract

A novel approach to study radiation track structure with nanometer-equivalent resolution

Cited by 18 publications

References 12 publications

Nanodosimetry – on the ''tracks'' of biological radiation effectiveness

Nanodosimetry – on the ''tracks'' of biological radiation effectiveness

Feasibility study of macroscopic simulations of nanodosimetric parameters for proton therapy

Quest for New Data: Ionizing Radiation Metrology in the Presence of Laser-Assisted Scattering Processes

Contact Info

Product

Resources

About