Estimation of the RBE of mammography-quality beams using a combination of a Monte Carlo code with a B-DNA geometrical model

Bernal, Mario A.; deAlmeida, C. E.; David, M; Pires, E J

doi:10.1088/0031-9155/56/23/004

Cited by 13 publications

(14 citation statements)

References 32 publications

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“…In our simulation, an RBE of 1.3 for DSB induction was observed for 40 or 220 kVp with respect to 4 MV, which is similar to simulated RBEs reported earlier [29].…”

Section: Discussionsupporting

confidence: 90%

“…Yields of DSBs, as well as their spatial distribution and especially their proximity, play an important role in the formation of chromosome aberrations and other cellular endpoints such as cell death [24,25,27,28]. However, it should be noted that for the same biological endpoint of interest and radiation quality, RBE values from the literature can present great variability [29].…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Radio-Induced Damage in Endothelial Cells Irradiated with 40 kVp, 220 kVp, and 4 MV X-rays by Means of Micro and Nanodosimetric Calculations

Tang

Bueno

Meylan³

et al. 2019

IJMS

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The objective of this work was to study the differences in terms of early biological effects that might exist between different X-rays energies by using a mechanistic approach. To this end, radiobiological experiments exposing cell monolayers to three X-ray energies were performed in order to assess the yields of early DNA damage, in particular of double-strand breaks (DSBs). The simulation of these irradiations was set in order to understand the differences in the obtained experimental results. Hence, simulated results in terms of microdosimetric spectra and early DSB induction were analyzed and compared to the experimental data. Human umbilical vein endothelial cells (HUVECs) were irradiated with 40, 220 kVp, and 4 MV X-rays. The Geant4 Monte Carlo simulation toolkit and its extension Geant4-DNA were used for the simulations. Microdosimetric calculations aiming to determine possible differences in the variability of the energy absorbed by the irradiated cell population for those photon spectra were performed on 10,000 endothelial cell nuclei representing a cell monolayer. Nanodosimetric simulations were also carried out using a computation chain that allowed the simulation of physical, physico-chemical, and chemical stages on a single realistic endothelial cell nucleus model including both heterochromatin and euchromatin. DNA damage was scored in terms of yields of prompt DSBs per Gray (Gy) and per giga (109) base pair (Gbp) and DSB complexity was derived in order to be compared to experimental data expressed as numbers of histone variant H2AX (γ-H2AX) foci per cell. The calculated microdosimetric spread in the irradiated cell population was similar when comparing between 40 and 220 kVp X-rays and higher when comparing with 4 MV X-rays. Simulated yields of induced DSB/Gy/Gbp were found to be equivalent to those for 40 and 220 kVp but larger than those for 4 MV, resulting in a relative biological effectiveness (RBE) of 1.3. Additionally, DSB complexity was similar between the considered photon spectra. Simulated results were in good agreement with experimental data obtained by IRSN (Institut de radioprotection et de sûreté nucléaire) radiobiologists. Despite differences in photon energy, few differences were observed when comparing between 40 and 220 kVp X-rays in microdosimetric and nanodosimetric calculations. Nevertheless, variations were observed when comparing between 40/220 kVp and 4 MV X-rays. Thanks to the simulation results, these variations were able to be explained by the differences in the production of secondary electrons with energies below 10 keV.

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“…In our simulation, an RBE of 1.3 for DSB induction was observed for 40 or 220 kVp with respect to 4 MV, which is similar to simulated RBEs reported earlier [29].…”

Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Assessment of Radio-Induced Damage in Endothelial Cells Irradiated with 40 kVp, 220 kVp, and 4 MV X-rays by Means of Micro and Nanodosimetric Calculations

Tang

Bueno

Meylan³

et al. 2019

IJMS

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“…sharper lateral dose fall-off) [23], less radiation leakage that implies lower peripheral dose, and a broader range of applicator sizes, resulting in a more conformal treatment. For these reasons, EBT is a promising technique for the treatment of skin lesions.…”

Section: Discussionmentioning

confidence: 99%

“…The RBE depends on the photon spectrum and the dose per fraction applied. After a review of the literature [18,19,20,21,22,23,24], it was estimated that the RBE for a 69.5 kVp X-ray source, such as the one used by Esteya ® , is around 1.15. Based on this analysis, the same clinical results achieved with the Valencia applicators could be expected by prescribing 7 Gy/1.15 = 6.1 Gy per fraction, during 6 fractions, with 2 fractions per week.…”

Section: Rationale For the Study Fractionation Schedulesmentioning

confidence: 99%

Electronic brachytherapy for superficial and nodular basal cell carcinoma: a report of two prospective pilot trials using different doses

Ballester‐Sánchez¹,

Pons-Llanas

Candela-Juan

et al. 2016

jcb

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Purpose: Basal cell carcinoma (BCC) is a very common cancer in the Caucasian population. Treatment aims to eradicate the tumor with the lowest possible functional and aesthetic impact. Electronic brachytherapy (EBT) is a treatment technique currently emerging. This study aims to show the outcomes of two consecutive prospective pilot clinical trials using different radiation doses of EBT with Esteya ® EB system for the treatment of superficial and nodular basal cell carcinoma.Material and methods: Two prospective, single-center, non-randomized, pilot studies were conducted. Twenty patients were treated in each study with different doses. The first group (1) was treated with 36.6 Gy in 6 fractions of 6.1 Gy, and the second group (2) with 42 Gy in 6 fractions of 7 Gy. Cure rate, acute toxicity, and late toxicity related to cosmesis were analyzed in the two treatment groups.Results: In group 1, a complete response in 90% of cases was observed at the first year of follow-up, whereas in group 2, the complete response was 95%. The differences with reference to acute toxicity and the cosmetic results between the two treatment groups were not statistically significant.Conclusions: Our initial experience with Esteya ® EB system to treat superficial and nodular BCC shows that a dose of 36.6 Gy and 42 Gy delivered in 6 fraction of 7 Gy achieves a 90% and 95% clinical cure rate at 1 year, respectively. Both groups had a tolerable toxicity and a very good cosmesis. The role of EBT in the treatment of BCC is still to be defined. It will probably become an established option for selected patients in the near future.

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“…The RBE 37 value is likely to be proportional to the number of DSBs. Alternatively the RBE value can be obtained by calculating the relative number of DSBs (when we see the number of DSBs as an endpoint of cell damage) [47]. Since the parameter k is proportional to the number of foci, the ratio of k has to be proportional to the RBE.…”

Section: Discussionmentioning

confidence: 99%

Quantitative estimation of DNA damage by photon irradiation based on the microdosimetric-kinetic model

Matsuya

Ohtsubo

Tsutsumi

et al. 2014

Journal of Radiation Research

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The microdosimetric-kinetic (MK) model is one of the models that can describe the fraction of cells surviving after exposure to ionizing radiation. In the MK model, there are specific parameters, k and yD, where k is an inherent parameter to represent the number of potentially lethal lesions (PLLs) and yD indicates the dose-mean lineal energy in keV/μm. Assuming the PLLs to be DNA double-strand breaks (DSBs), the rate equations are derived for evaluating the DSB number in the cell nucleus. In this study, we estimated the ratio of DSBs for two types of photon irradiation (6 MV and 200 kVp X-rays) in Chinese hamster ovary (CHO-K1) cells and human non-small cell lung cancer (H1299) cells by observing the surviving fraction. The estimated ratio was then compared with the ratio of γ-H2AX foci using immunofluorescent staining. For making a comparison of the number of DSBs among a variety of radiation energy cases, we next utilized the survival data in the literature for both cells exposed to other photon types, such as 60Co γ-rays, 137Cs γ-rays and 100 kVp X-rays. The ratio of DSBs based on the MK model with conventional data was consistent with the ratio of γ-H2AX foci numbers, confirming that the γ-H2AX focus is indicative of DSBs. It was also shown that the larger yD is, the larger the DSB number is. These results suggest that k and yD represent the characteristics of the surviving fraction and the biological effects for photon irradiation.

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Estimation of the RBE of mammography-quality beams using a combination of a Monte Carlo code with a B-DNA geometrical model

Cited by 13 publications

References 32 publications

Assessment of Radio-Induced Damage in Endothelial Cells Irradiated with 40 kVp, 220 kVp, and 4 MV X-rays by Means of Micro and Nanodosimetric Calculations

Assessment of Radio-Induced Damage in Endothelial Cells Irradiated with 40 kVp, 220 kVp, and 4 MV X-rays by Means of Micro and Nanodosimetric Calculations

Electronic brachytherapy for superficial and nodular basal cell carcinoma: a report of two prospective pilot trials using different doses

Quantitative estimation of DNA damage by photon irradiation based on the microdosimetric-kinetic model

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