A Monte Carlo Simulation of Auger Cascades

Pomplun, Ekkehard; Booz, J.; Charlton, D.E.

doi:10.2307/3576938

Cited by 102 publications

(59 citation statements)

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“…Table I shows the reported energy E 0 , frequency distribution N(E 0 ), and their product Δ for Auger electrons energies between 5 and 18 eV from the nuclear decay of a single 125 I. 19,47 Below 5 eV, electrons mostly deposit their energies within DNA via vibrational excitation, which has negligible contribution to the total absorbed dose of DNA by ULEEs (i.e., 3%) compared with electronic excitation and ionization processes (i.e., 39% and 58%, respectively). 22 Furthermore, the reported threshold energy for the induction of DSB by ULEEs is 6-7 eV.…”

Section: A Absorbed Dose In Dna By Auger Electrons Of 5-18 Evmentioning

confidence: 99%

“…16 Inclusion of O-shell Coster-Kronig electrons in the nanodosimetry of 125 I, for example, increases the mean energy deposited in a cylinder of radius 1.15 nm by a factor of 3. 16,18,19 In addition, Auger electrons and x rays with energies higher than 20 eV produce ULEEs in each ionization interaction. Therefore, calculation of absorbed doses and quantification of subsequent molecular modifications by ULEE irradiation are essential steps to accurately estimate the biological effects of any type of radiation, particularly that of Auger electrons.…”

Section: Introductionmentioning

confidence: 99%

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Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

2014

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Purpose-The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides.Methods-Absorbed dose and stopping cross section for the Auger electrons of 5-18 eV emitted by 125 I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single-and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure-response curves for induction of DNA strand breaks.Results-For a single decay of 125 I within DNA, the Auger electrons of 5-18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm 3 volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break.Conclusions-Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should be considered in the dosimetry calculation of such radionuclides. Moreover, absorbed dose is not an appropriate physical parameter for nanodosimetry. Instead, stopping cross section, which describes the probability of energy deposition in a target molecule can be an appropriate nanodosimetric parameter. The stopping cross section is correlated with a damaging cross section a)Author to whom correspondence should be addressed. CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript (e.g., cross section for the double-strand break formation) to quantify the number of each specific lesion in a target molecule for each nuclear decay of a single Auger-electron emitting radionuclide.

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Section: A Absorbed Dose In Dna By Auger Electrons Of 5-18 Evmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

2014

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“…The choice of the spatial step ∆x depends on the value of the temporal step ∆t and therefore by accuracy and stability of the solutions of the diffusion equation (12).…”

Section: Resultsmentioning

confidence: 99%

“…To access this formulation we have used the continuous finite element method [12], [13] and the method of centered differences [10]. Thus, the explicit method can replace the equation (11) by the following algebraic equation:…”

Section: Figure 2: Immediate Neighboring Of An Elementary Volume Insimentioning

confidence: 99%

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Development of a hybrid model to quantify the single and double strand breaks following the iron 57 de-excitation

Oudira¹,

Lotfi²,

Safi³

2017

Pressacademia

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The therapeutic utility of certain Auger emitters such as iodine-125 depends on their position within the cell nucleus. Or diagnostically, and to maintain as low as possible cell damage, it is preferable to have radionuclide localized outside the cell or at least the core. One solution to this problem is to consider markers capable of conveying anticancer drugs to the tumor site regardless of their location within the human body. The objective of this study is to simulate the impact of a complex such as bleomycin on single and double strand breaks in the DNA molecule. Indeed, this simulation consists of the following transactions: Construction of BLM -Fe-DNA complex, simulation of the electron's transport from the metastable state excitation of Fe 57 by the Monte Carlo method, treatment of chemical reactions in the considered environment by the diffusion equation. For physical, physico-chemical and finally chemical steps, the geometry of the complex is considered as a sphere of 50 nm centered on the binding site , and the mathematical method used is called step by step based on Monte Carlo codes. ________________________________________________________________________________________________________________

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Targeted Auger Electron Radiotherapy of Malignancies

Reilly

Kassis

2010

Monoclonal Antibody and Peptide‐Targeted Radiotherapy of Cancer

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A Monte Carlo Simulation of Auger Cascades

Cited by 102 publications

References 1 publication

Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5-18 eV) electron interactions with DNA

Development of a hybrid model to quantify the single and double strand breaks following the iron 57 de-excitation

Targeted Auger Electron Radiotherapy of Malignancies

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