Computational approach to determine the relative biological effectiveness of fast neutrons using the Geant4-DNA toolkit and a DNA atomic model from the Protein Data Bank

A microdosimetric analysis of the interactions of mono-energetic neutrons with human tissue

“…A version of this algorithm has already been implemented within Geant4-DNA by the author. A multi-scale MC approach may also be taken in the vein of a recent publication by Zabihi et al [88]. These techniques seek to explicitly model not just the physical interactions of radiation, but also the subsequent physicochemical and chemical stages in order to predict DNA damage.…”

“…The Baiocco et al [63] study served as a motivation for the research presented in this thesis. Due to the explicit generation and sampling of tracks reported here, however, a full comparison between end results cannot be made because the lack of low-energy heavy ion transport in Geant4-DNA precludes studies of neutron energies above ∼ 14 MeV [88] (as was done in Baiocco et al [63]). Rather, their simulation set-up serves as the basis for the methods presented in Chapter 5, while their search for a physical explanation for trends observed in published radiation weighting factors informs the direction of Chapter 7.…”

Determination of fast neutron RBE using a fully mechanistic computational model

“…The RBE is defined as a function of the biological endpoint and dose or dose per fraction. One of these endpoints is DSB induction [22,50], which was used in this work. DSB yields were calculated for all neutron energies and 60 Co γrays.…”

“…This work refers to the most relevant works found in the literature. Zabihi et al [22] proposed an approach to estimate RBE of fast neutrons with energies ranging from 0.1 MeV to 14 MeV using the Geant4 toolkit. This approach used an atomic resolution DNA geometrical model extracted from the Protein Data Bank.…”

Investigação >i<ab initio>/i< dos mecanismos de formação de nanoflocos de dicalcogenetos de metais de transição

“…1 Este esforço se deve à importância que este tipo de interação possui em sistemas fundamentais para a química, biologia e estudos de estado sólido. Além do mais, interações de vdW estão presentes em sistemas iônicos ou covalentes, sendo, no entanto, preponderantes em sistemas que apresentem partes fracamente ligadas, como em DNA, [136,137] micelas [138,139] ou interações verticais envolvendo dicalcogenetos de metais de transição. [50,62] As interações de van der Waals são de natureza eletrostática e surgem de flutuações quânticas e térmicas, [140,141] o que faz com que estas possuam correspondência com o movimento dos elétrons de um sistema, uma vez que as flutuações que dão origem às interações de vdW podem ser associadas com flutuações da densidade de carga.…”