FELIPE BELONSI DE CINTRA
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Artigo IPEN-doc 16675 Espectroscopia gama estimulada por neutrons rápidos de uma fonte Am-Be na estimativa da concentração de metais usando MCNP52010 - SANTOS, ADIMIR dos; CINTRA, FELIPE B. de; YORIYAZ, HELIO; VIANA, RODRIGO S.S.Utilizando o código de transporte de radiação MCNP5 foi simulado o espectro de emissão gama de amostras metálicas de proporção isotrópica natural de Fe, Al, Ni e Cu por reações (n,n’) estimuladas por nêutrons rápidos de uma fonte de Am-Be com o objetivo de estimar tanto a presença como a concentração dos metais irradiados. As amostras foram simuladas como cilindros concêntricos sólidos. Para o Fe também foi modelado um objeto simulador cilíndrico de água com volume de 3,4x103 cm 3 , o metal estava uniformemente diluídos na solução aquosa em diferentes concentrações. Também foram modelados a fonte de Am-Be e os detectores HPGe. Os espectros obtidos mostraram picos de emissão característicos de todos os metais irradiados e as concentrações foram estimadas com sucesso pela relação direta com a contagem dentro da margem de erro estatístico.Artigo IPEN-doc 15004 Electron absorbed dose comparison between MCNP5 and penelope monte carlo code for microdosimetry2009 - CINTRA, FELIPE B.; YORIYAZ, HELIOArtigo IPEN-doc 14098 Analysis of ct and pet/spect images for dosimetry calculation2009 - MASSICANO, FELIPE; MASSICANO, ADRIANA V.F.; SILVA, NATANAEL G.; CINTRA, FELIPE B.; CARVALHO, RODRIGO M.; YORIYAZ, HELIOArtigo IPEN-doc 14652 Physical models, cross sections, and numerical approximations used in MCNP and GEANT4 Monte Carlo codes for photon and electron absorbed fraction calculation2009 - YORIYAZ, HELIO; MORALLES, MAURICIO; SIQUEIRA, PAULO de T.D.; GUIMARAES, CARLA da C.; CINTRA, FELIPE B.; SANTOS, ADIMIR dosPurpose: Radiopharmaceutical applications in nuclear medicine require a detailed dosimetry estimate of the radiation energy delivered to the human tissues. Over the past years, several publications addressed the problem of internal dose estimate in volumes of several sizes considering photon and electron sources. Most of them used Monte Carlo radiation transport codes. Despite the widespread use of these codes due to the variety of resources and potentials they offered to carry out dose calculations, several aspects like physical models, cross sections, and numerical approximations used in the simulations still remain an object of study. Accurate dose estimate depends on the correct selection of a set of simulation options that should be carefully chosen. This article presents an analysis of several simulation options provided by two of the most used codes worldwide:MCNP and GEANT4. Methods: For this purpose, comparisons of absorbed fraction estimates obtained with different physical models, cross sections, and numerical approximations are presented for spheres of several sizes and composed as five different biological tissues. Results: Considerable discrepancies have been found in some cases not only between the different codes but also between different cross sections and algorithms in the same code. Maximum differences found between the two codes are 5.0% and 10%, respectively, for photons and electrons. Conclusion: Even for simple problems as spheres and uniform radiation sources, the set of parameters chosen by any Monte Carlo code significantly affects the final results of a simulation, demonstrating the importance of the correct choice of parameters in the simulation.