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Validation of the TOPAS Monte-Carlo Code of the Off-Field Dose of a 6 MV Synergy Linac

Journal of Biosciences and Medicines 2024年第7期12卷 38-54页

作者： kodjo joel fabrice n’guessan Ibrahima Sakho Bogbé D. L. H. Gogon Department of Physics and Chemistry Faculty of Sciences and Technology Iba Der Thiam University of This This Senegal International Cancer Center of Dakar Dakar Senegal Department of Physics Faculty of Sciences and Technology Flix Houphouet Boigny University of Abidjan Abidjan Cte dIvoire

The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calculating these doses. MC simulation model based on the Particle Simulation Tool (TOPAS) has been developed to simulate the off-field dose of an Elekta Synergy linear accelerator (Linac) emitting 6 MV photons. Measurements were taken in a water phantom using an ionization chamber to validate this model. The Percentage Depth Dose (PDD) at the depth of 0.0, 5.0, 10.0 and 15.0 cm from the beam axis for a 10 × 10 cm2 field size was measured and simulated. Off-field dose profiles at the depth of 1.5 (dmax), 5.0 and 10.0 cm for field sizes of 5 × 5, 10 × 10, 15 × 15, and 20 × 20 cm2 respectively were measured and simulated. Comparison of measured and simulated off-field dose values showed a good agreement. The average gamma passing rate of the PDDs and profiles curves for off-field doses were 87.5% and 98.11% respectively. The local dose difference based on the PDD curve between the measured and simulated was less than 6.0 % for all locations. For all field size considered in this study, the average difference between profile curves for off-field dose measured and simulated was 9.1%. PDDs and Profiles curves for off-field dose simulation uncertainties were less than 2.0% and 1.0% respectively. TOPAS-MC simulation model developed is a good representation of our 6 MV Linac Elekta Synergy for assessing off-field dose, which would be the primary cause of some secondary cancers.

关键词： Radiotherapy Off-Field Dose Secondary Cancer TOPAS-MC Simulation Dosimetry

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Enhancing Precision in Radiotherapy Delivery: Validating Monte Carlo Simulation Models for 6 MV Elekta Synergy Agility LInAC Photon Beam Using Two Models of the GAMOS Code

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World Journal of nuclear Science and Technology 2024年第2期14卷 146-163页

作者： nogaye ndiaye Oumar ndiaye Papa Macoumba Faye kodjo Joël fabrice n’guessan Djicknack Dione Khady Sy Moussa Hamady Sy Jean Paul Latyr Faye Alassane Traoré Ababacar Sadikhe ndao Institute of Applied nuclear Technology University Cheikh Anta Diop Dakar Senegal International Cancer Center of Dakar Dakar Senegal Department of Physics Faculty of Sciences and Technology University Cheikh Anta Diop Dakar Senegal

The most crucial requirement in radiation therapy treatment planning is a fast and accurate treatment planning system that minimizes damage to healthy tissues surrounding cancer cells. The use of Monte Carlo toolkits has become indispensable for research aimed at precisely determining the dose in radiotherapy. Among the numerous algorithms developed in recent years, the GAMOS code, which utilizes the Geant4 toolkit for Monte Carlo simula-tions, incorporates various electromagnetic physics models and multiple scattering models for simulating particle interactions with matter. This makes it a valuable tool for dose calculations in medical applications and throughout the patient’s volume. The aim of this present work aims to vali-date the GAMOS code for the simulation of a 6 MV photon-beam output from the Elekta Synergy Agility linear accelerator. The simulation involves mod-eling the major components of the accelerator head and the interactions of the radiation beam with a homogeneous water phantom and particle information was collected following the modeling of the phase space. This space was po-sitioned under the X and Y jaws, utilizing three electromagnetic physics mod-els of the GAMOS code: Standard, Penelope, and Low-Energy, along with three multiple scattering models: Goudsmit-Saunderson, Urban, and Wentzel-VI. The obtained phase space file was used as a particle source to simulate dose distributions (depth-dose and dose profile) for field sizes of 5 × 5 cm2 and 10 × 10 cm2 at depths of 10 cm and 20 cm in a water phantom, with a source-surface distance (SSD) of 90 cm from the target. We compared the three electromagnetic physics models and the three multiple scattering mod-els of the GAMOS code to experimental results. Validation of our results was performed using the gamma index, with an acceptability criterion of 3% for the dose difference (DD) and 3 mm for the distance-to-agreement (DTA). We achieved agreements of 94% and 96%, respective

关键词： GAMOS Monte Carlo LInAC Radiotherapy Dose Distribution Phase Space Gamma Index 6 MV Photon Beam

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Isolation and Spasmolytic Evaluation of new Alkaloids from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae)

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Pharmacology & Pharmacy 2013年第9期4卷 684-688页

作者： Amenan Genevieve n’guessan-Irie joel Dade Pierre Champy n’doua Gisele Siransy-Kouakou Veronique Leblais Chimie des Substances naturelles CNRS UMR 8076 BioCISChatenay-MalabryFrance Laboratoire de Pharmacologie et Physiologie UFR Sciences Pharmaceutiques et BiologiquesUniversiteFelix Houphouet-BoignyAbidjanRepublique de Cote d’Ivoire Facultede Pharmacie UniversiteParis-Sud 11Chatenay-MalabryFrance InSERM UMR-S 769 Chatenay-MalabryFrance

Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae) root bark is used in Ivorian Traditional Medicine to treat asthma, which is a respiratory disorder characterized by inflammation and the restriction of tracheal muscles obstructing the air circulation. The tracheal relaxant effect of a crude aqueous-alcoholic extract of the plant root bark was previously shown. For the present study, alkaloids were isolated from the same extract and investigated ex vivo in C57Bl/6j mice isolated trachea contracted with carbachol 1 μM, in comparison with a reference bronchodilatator, i.e. salbutamol. Two extraction procedures allowed isolating 2 Alkaloids that monodimensional and bi-dimensional nuclear magnetic resonance (nMR) and mass specters allowed identifying a pyrolidine structure type nucleus with a long bi-hydroxyled alkyl chain. Alkaloid 1, carrier of a sugar, is a glycoside of Alkaloid 2. Both alkaloids induced similar spasmolytic effects, but Alkaloid 1 was more effective than Alkaloid 2 at 9 × 10-6 M (p nd 9 × 10-5 M (p nduced its spasmolytic effect in a different way, and its maximal effect Emax (less than 30%) was obtained at 9 × 10-6 M, while Emax of both alkaloids (100%) was obtained at 3 × 10-4 M.

关键词： Alkaloids Isolated Plant Spasmolytic Asthma

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Influence of Mineral Fertilization on the Capacity of nodulation of Three Species of Legumes(Groundnut,Cowpea and Soybean)

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American Journal of Plant Sciences 2019年第12期10卷 2208-2218页

作者： Kouassi n’dri Jacob Kouame n’guessan Alui Konan Alphonse Yao Koffi joel Ayolie Koutoua Yatty Kouadio Justin Laboratory of Improvement of Agricultural Production University Jean Lorougnon GUEDEAgroforestry UFRDaloaCote d’Ivoire Geosciences Department University Péléforo Gbon CoulibalyBiological SciencesUFRKorhogoCote d’Ivoire

Groundnut (Arachis hypogaea), cowpea (Vigna unguiculata) and soybean (Vigna radiata) are the main food legumes grown in Cote d’Ivoire and the localities of Haut-Sassandra. These legumes are highly valued for their nutritional, agronomic and economic value. Groundnut, cowpea and soybean are the main food legumes grown in Cote d’Ivoire and in the localities of Haut-Sassandra. On the other hand, Ivorian soils are characterized by a tendency towards acidification and a decrease in the content of nutrients such as phosphorus and nitrogen which have a direct impact on the products. To restore soil fertility, farmers use mineral fertilization. However, this fertilization has an influence on the nodulation of these legumes. The study took place at Jean Lorougnon University. We adopted a completely random experimental block device. The parameters measured included the number of nodules, the length and weight of the plant, the length and weight of the root system. Our results showed that mineral fertilization reduced the nodulation capacity of legumes. However, a small dose of phosphorus ( g) would be required for early growing legumes.

关键词： Mineral Fertilization Legumes nodulation Phosphorus

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Theoretical Studies of Photodynamic Therapy Properties of Azopyridine δ-OsCl2(Azpy)2Complex as a Photosensitizer by a TDDFT Method

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Computational Chemistry 2021年第1期9卷 64-84页

作者： Wawohinlin Patrice Ouattara Kafoumba Bamba Affi Sopi Thomas Fatogoma Diarrassouba Lamoussa Ouattara Massapihanhoro Pierre Ouattara Kouakou nobel n'guessan Mamadou Guy Richard Kone Charles Guillaume kodjo nahossé Ziao Laboratoire de Thermodynamique et de PHysico-Chimie du Milieu UFR-SFA Université NanguiAbrogoua Abidjan C&#244te d’Ivoire

Photochemical reactions have an important place in photodynamic treatments. A good use of this therapeutic method requires a good mastery of the mechanisms of the reactions involved. Therefore, we have explored in this work the photosensitization mechanism of an organometallic complex of azopyridine δ-OsCl2(Azpy)2 through a calculation with the method of Time Dependent Density Functional Theory TDDFT. First, we evaluated the effect of polar and non-polar solvents on the triplet and singlet excited states of this complex. Then secondly, we highlighted the photosensitization mechanism to understand how the complex acts over the diseased cells. These investigations have shown that the δ-OsCl2(Azpy)2 complex is likely to develop photodynamic activity according to two mechanisms: on one hand, it can generate damage to DnA bases or target tissues indirectly through the production of singlet oxygen in water and in DMSO. On the second hand, through the production of the anionic superoxide radical in water can act directly or indirectly on these substrates. In addition, polar solvents are assumed to better carry out the photochemical reactions of this azopyridine complex of osmium.

关键词： Time Dependent-Density Functional Theory Azopyridine Excited States Photosensitization Photodynamic Therapy Osmium

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