Microdosimetric investigation of the radiation quality of low-medium energy electrons using Geant4-DNA

Kyriakou, Ioanna; Tremi, Ioanna; Georgakilas, Alexandros G.; Emfietzoglou, Dimitris

doi:10.1016/j.apradiso.2021.109654

Cited by 20 publications

(31 citation statements)

References 110 publications

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“…Recently, new energy‐loss and physics models have been implemented in Geant4‐DNA, which are expected to influence the chemistry of liquid water considerably and, hence, affect the biophysical simulations by addressing the vital role of spatial extension and pattern of low‐energy electrons 31,32 . These improvements are crucial for microscopic bio‐structure investigations, in view of the crucial role that low‐energy electrons play in microdosimetric, DNA damage, and RBE calculations 33–35 . The cross‐section models used in the present work—applying to electrons of 11 eV to 255 keV for elastic, excitation, and ionization processes—were G4DNACPA100ElasticModel, G4DNACPA100ExcitationModel, and G4DNACPA100IonizationModel.…”

Section: Methodsmentioning

confidence: 99%

“…31,32 These improvements are crucial for microscopic biostructure investigations, in view of the crucial role that low-energy electrons play in microdosimetric, DNA damage, and RBE calculations. [33][34][35] The crosssection models used in the present work-applying to electrons of 11 eV to 255 keV for elastic, excitation, and ionization processes-were G4DNACPA100 ElasticModel, G4DNACPA100ExcitationModel, and G4DNACPA100IonizationModel. Using the CPA100 physics constructor in Geant4-DNA, referred to as G4EmDNAPhysics_option6, one obtains electron stopping powers that are, compared to the default constructor, closer to the values proposed by ICRU90 for liquid water.…”

Section: Methodsmentioning

confidence: 99%

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DNA damage and microdosimetry for carbon ions: Track structure simulations as the key to quantitative modeling of radiation‐induced damage

Moeini

Mokari²

2022

Medical Physics

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Purpose Dose distribution in carbon‐ion irradiations is generally envisaged to have therapeutic advantages over protons, primarily due to the carbon ion's comparatively higher relative biological effectiveness in the tumor than in the encompassing healthy tissues. The objective of this work was to simulate the overall physical and chemical reactions of primary carbon ions impinging on liquid water and, as such, to investigate the DNA‐damage yields in the form of strand breaks (SBs) and in connection with the expected microdosimetric quantities. Materials and methods Using a B‐DNA model and Geant4‐DNA, we simulated the primary and secondary interactions in a spherical medium of water. Subsequently, we categorized DNA damages based on their complexity utilizing the concept of μ‐randomness. We assumed a threshold of 17.5 eV for a direct SB and a probability of 0.13 for an indirect SB triggered by chemical reactions of hydroxyl radicals. Microdosimetric quantities were extracted for three cylindrical volumes representing typical subcellular organisms. Results For fully ionized carbons of 8–256 MeV/u, the yield results appeared to be considerably influenced by the chemical reactions—indicating the important role of secondary electrons in inflicting damage. However, it was mostly the direct‐damage spectrum that determined the overall shape of the damage spectrum. At all primary energies, it was more probable to break each DNA strand at one point—the two points being less than 10 bp apart—than to break only one strand at two random points. Unlike proton's mean‐specific‐energy results, which showed more sensitivity to the volume increase of the smallest cylinder than of the larger ones, carbon‐ion results showed no such sensitivity. Conclusion The growth of the yield ratio of the single‐ and double‐strand breaks (DSB) with the particle energy was estimated for protons to be about 2 times that of alphas and 92 times that of carbon ions. Unlike the proton results, which suggested significant correlations between the DSB yields and mean‐specific (and lineal) energies, carbon ions exhibited no such correlations.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

DNA damage and microdosimetry for carbon ions: Track structure simulations as the key to quantitative modeling of radiation‐induced damage

Moeini

Mokari²

2022

Medical Physics

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“…For almost all types of IRs, the induction of dense ionizations and closely spaced DNA lesions are considered a signature for these types of radiations from low energy photons and electrons [60] to space radiations and a major contribution in the detrimental effects of IRs and instigator of biological responses at the cellular or tissue level. Furthermore, the genes BAX, BCL2, CCND1, and TNF were found to be differentially expressed in mammalian cancer cells exposed to medium-to-high-LET radiation versus non-irradiated cells.…”

Section: Prognostic Value Of Dna Damage-associated Genes In Diverse Cancersmentioning

confidence: 99%

In Silico Investigation of the Biological Implications of Complex DNA Damage with Emphasis in Cancer Radiotherapy through a Systems Biology Approach

et al. 2021

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Different types of DNA lesions forming in close vicinity, create clusters of damaged sites termed as “clustered/complex DNA damage” and they are considered to be a major challenge for DNA repair mechanisms resulting in significant repair delays and induction of genomic instability. Upon detection of DNA damage, the corresponding DNA damage response and repair (DDR/R) mechanisms are activated. The inability of cells to process clustered DNA lesions efficiently has a great impact on the normal function and survival of cells. If complex lesions are left unrepaired or misrepaired, they can lead to mutations and if persistent, they may lead to apoptotic cell death. In this in silico study, and through rigorous data mining, we have identified human genes that are activated upon complex DNA damage induction like in the case of ionizing radiation (IR) and beyond the standard DNA repair pathways, and are also involved in cancer pathways, by employing stringent bioinformatics and systems biology methodologies. Given that IR can cause repair resistant lesions within a short DNA segment (a few nm), thereby augmenting the hazardous and toxic effects of radiation, we also investigated the possible implication of the most biologically important of those genes in comorbid non-neoplastic diseases through network integration, as well as their potential for predicting survival in cancer patients.

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“…This connection stems from the recognition that radiation quality originates from the spatial distribution of the discrete energy deposition events in the irradiated medium at the molecular scale [15]. Thus, MCTS codes have been widely used for RBE (relative biological effectiveness) studies in radiotherapy and radiation protection practice [16][17][18][19][20][21]. Since electrons form the main product of all types of ionizing radiation with significant contribution to absorbed dose and biological damage, the details of their interactions with matter consist a priority of every MCTS code [22].…”

Section: Introductionmentioning

confidence: 99%

Status and Extension of the Geant4-DNA Dielectric Models for Application to Electron Transport

2022

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The development of accurate physics models that enable track structure simulations of electrons in liquid water medium over a wide energy range, from the eV to the MeV scale, is a subject of continuous efforts due to its importance (among other things) in theoretical studies of radiation quality for application in radiotherapy and radiation protection. A few years ago, the Geant4-DNA very low-energy extension of the Geant4 Monte Carlo code had offered to users an improved set of physics models for discrete electron transport below 10 keV. In this work we present refinements to this model set and its extension to energies up to 1 MeV. Preliminary comparisons against the existing Geant4-DNA physics models with respect to total and differential ionization cross sections of electrons in liquid water are reported and discussed.

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Microdosimetric investigation of the radiation quality of low-medium energy electrons using Geant4-DNA

Cited by 20 publications

References 110 publications

DNA damage and microdosimetry for carbon ions: Track structure simulations as the key to quantitative modeling of radiation‐induced damage

DNA damage and microdosimetry for carbon ions: Track structure simulations as the key to quantitative modeling of radiation‐induced damage

In Silico Investigation of the Biological Implications of Complex DNA Damage with Emphasis in Cancer Radiotherapy through a Systems Biology Approach

Status and Extension of the Geant4-DNA Dielectric Models for Application to Electron Transport

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