Synchrotron X-ray Irradiation of a Rat’s Head Model: Monte Carlo Study of Chromatic Gel Dosimetry

Accurate treatment planning in radiotherapy essentially decreases damage to healthy tissue surrounding the tumor. Due to plans to use a direct, highly collimated, narrow beam with high intensity to treat small area tumors, researchers have studied microbeam radiation therapy extensively. Using a synchrotron beam as the radiation source may help to limit damage, but treatment planning using computerized simulations and dosimetry is still necessary to achieve optimal results. For this purpose, PDA-gel dosimeters were developed and their sensitivity around a 150 keV induced synchrotron X-ray radiation beam was examined via Monte Carlo simulations using the EGS5 code system. The microbeam development is now at the animal study stage. In this study, we simulate the irradiation of a rat’s brain. The simulation results obtained spectra for two types of PDA-gel dosimeters that were compared with the spectrum obtained in a modelized brain tumor of a rat. Additionally, percentage depth dose curves were calculated for the brain tissue and the two gels. Correction equations for the dosimeters were obtained from the dose-difference plots. For further references, these equations can be used to calculate the actual dose in a brain tumor in a rat. The Monte Carlo simulations demonstrate that PDA-gel dosimeters can be used for treatment planning using synchrotron irradiations.

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A microCT X-ray head model for spectra generation with Monte Carlo simulations

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2006.08.038 ◽

2006 ◽

Vol 569 (2) ◽

pp. 373-377 ◽

Cited By ~ 8

Author(s):

R. Taschereau ◽

P.L. Chow ◽

J.S. Cho ◽

A.F. Chatziioannou

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Head Model ◽

X Ray

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Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164854 ◽

1996 ◽

Vol 54 ◽

pp. 478-479

Author(s):

Matthew T. Johnson ◽

Ian M. Anderson ◽

Jim Bentley ◽

C. Barry Carter

Keyword(s):

Monte Carlo ◽

Quantitative Analysis ◽

Monte Carlo Simulations ◽

Cross Section ◽

Spatial Resolution ◽

Low Voltage ◽

Magnesium Ferrite ◽

X Ray ◽

Interaction Volume ◽

Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

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Modular MA-XRF Scanner Development in the Multi-Analytical Characterisation of a 17th Century Azulejo from Portugal

Sensors ◽

10.3390/s21051913 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1913

Author(s):

Sergio Augusto Barcellos Lins ◽

Marta Manso ◽

Pedro Augusto Barcellos Lins ◽

Antonio Brunetti ◽

Armida Sodo ◽

...

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

17Th Century ◽

Scanning System ◽

X Ray ◽

Portable Instruments ◽

Complementary Techniques ◽

Non Destructive ◽

Suitable Technique ◽

Cobalt Blue

A modular X-ray scanning system was developed, to fill in the gap between portable instruments (with a limited analytical area) and mobile instruments (with large analytical areas, and sometimes bulky and difficult to transport). The scanner has been compared to a commercial tabletop instrument, by analysing a Portuguese tile (azulejo) from the 17th century. Complementary techniques were used to achieve a throughout characterisation of the sample in a complete non-destructive approach. The complexity of the acquired X-ray fluorescence (XRF) spectra, due to inherent sample stratigraphy, has been resolved using Monte Carlo simulations, and Raman spectroscopy, as the most suitable technique to complement the analysis of azulejos colours, yielding satisfactory results. The colouring agents were identified as cobalt blue and a Zn-modified Naples-yellow. The stratigraphy of the area under study was partially modelled with Monte Carlo simulations. The scanners performance has been compared by evaluating the images outputs and the global spectrum.

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Adsorption of H2 on Penta-Octa-Penta Graphene: Grand Canonical Monte Carlo Study

C – Journal of Carbon Research ◽

10.3390/c6020020 ◽

2020 ◽

Vol 6 (2) ◽

pp. 20

Author(s):

Maxim N. Popov ◽

Thomas Dengg ◽

Dominik Gehringer ◽

David Holec

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Hydrogen Adsorption ◽

Monte Carlo Study ◽

Adsorption Properties ◽

Cryogenic Temperatures ◽

Grand Canonical Monte Carlo ◽

New Material ◽

Grand Canonical ◽

Carbon Based

In this paper, we report the results of hydrogen adsorption properties of a new 2D carbon-based material, consisting of pentagons and octagons (Penta-Octa-Penta-graphene or POP-graphene), based on the Grand-Canonical Monte Carlo simulations. The new material exhibits a moderately higher gravimetric uptake at cryogenic temperatures (77 K), as compared to the regular graphene. We discuss the origin of the enhanced uptake of POP-graphene and offer a consistent explanation.

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