LUCIO PEREIRA NEVES
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Resumo IPEN-doc 26011 Evaluation of polymer gels using Monte Carlo simulations2018 - SANTOS, W.S.; NEVES, L.P.; PERINI, A.P.; BELINATO, W.; CALDAS, L.V.E.Artigo IPEN-doc 24798 Exposure to 137Cs deposited in soil – A Monte Carlo study2018 - SILVEIRA, LUCAS M. da; PEREIRA, MARCO A.M.; NEVES, LUCIO P.; PERINI, ANA P.; BELINATO, WALMIR; CALDAS, LINDA V.E.; SANTOS, WILLIAM S.In the event of an environmental contamination with radioactive materials, one of the most dangerous materials is 137Cs. In order to evaluate the radiation doses involved in an environmental contamination of soil, with 137Cs, we carried out a computational dosimetric study. We determined the radiation conversion coefficients (CC) for effective (E) and equivalent (H T) doses, using a male and a female anthropomorphic phantoms. These phantoms were coupled with the MCNPX (2.7.0) Monte Carlo simulation software, for three different types of soil. The highest CC[H T] values were for the gonads and skin (male) and bone marrow and skin (female). We found no difference for the different types of soil.Artigo IPEN-doc 24376 Occupational exposures during abdominal fluoroscopically guided interventional procedures for different patient sizes — A Monte Carlo approach2018 - SANTOS, WILLIAM S.; BELINATO, WALMIR; PERINI, ANA P.; CALDAS, LINDA V.E.; GALEANO, DIEGO C.; SANTOS, CARLA J.; NEVES, LUCIO P.In this study we evaluated the occupational exposures during an abdominal fluoroscopically guided interventional radiology procedure. We investigated the relation between the Body Mass Index (BMI), of the patient, and the conversion coefficient values (CC) for a set of dosimetric quantities, used to assess the exposure risks of medical radiation workers. The study was performed using a set of male and female virtual anthropomorphic phantoms, of different body weights and sizes. In addition to these phantoms, a female and a male phantom, named FASH3 and MASH3 (reference virtual anthropomorphic phantoms), were also used to represent the medical radiation workers. The CC values, obtained as a function of the dose area product, were calculated for 87 exposure scenarios. In each exposure scenario, three phantoms, implemented in the MCNPX 2.7.0 code, were simultaneously used. These phantoms were utilized to represent a patient and medical radiation workers. The results showed that increasing the BMI of the patient, adjusted for each patient protocol, the CC values for medical radiation workers decrease. It is important to note that these results were obtained with fixed exposure parameters.Resumo IPEN-doc 24504 Evaluation of polymer gels using Monte Carlo simulations2017 - SANTOS, W.S.; NEVES, L.P.; PERINI, A.P.; BELINATO, W.; CALDAS, L.V.E.The use of Monte Carlo simulations in dosimetry is a well established area of research, and several correction factors, for ionization chambers, are evaluated with these simulations. Some simulated values are considered even more reliable than the experimental measurements. Besides these uses with ionization chambers, Monte Carlo simulations may also be employed in the development and characterization of new dosimetric materials, as polymer gels. Polymer gels are largely employed in radiotherapy dosimetry to mimic human tissue [1,2]. New polymer gels were studied in order to better represent different organs or tissues, to provide more reliable results, or even to use different measurement techniques. The objective of this study is to evaluate the dosimetric properties of polymer gels, in relation to its mass-energy absorption coefficients, energy response and tissue equivalence. For this purpose the MCNPX Monte Carlo code was utilized. Four different materials, employed in radiotherapy dosimetry were evaluated in this work: MAGAS (methacrylic acid gelatine gel with ascorbic acid), MAGAT (methacrylic acid gelatine and tetrakis), AMPS (2-Acrylamido-2-MethylPropane Sulfonic acid) and MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper). For all simulations carried out, the values were within an acceptable uncertainty and in accordance to the expected results.Resumo IPEN-doc 24455 Avaliação dosimétrica de procedimentos de tomossíntese mamária2017 - NEVES, LUCIO P.; SILVA, RAYRE J.V.; PERINI, ANA P.; SANTOS, WILLIAM de S.; VEDOVATO, ULY P.Artigo IPEN-doc 24249 Exposition to 137Cs deposited in soil – a Monte Carlo study2017 - SILVEIRA, LUCAS M. da; PEREIRA, MARCO A.M.; NEVES, LUCIO P.; PERINI, ANA P.; BELINATO, WALMIR; CALDAS, LINDA V.E.; SANTOS, WILLIAM S.In the event of environmental contamination with radioactive materials, one of the most dangerous materials is 137Cs. In order to evaluate the radiation doses involved in an environmental contamination of soil, with 137Cs, we carried out a computational dosimetric study. We determined the radiation doses conversion coefficients (CC) for E and HT, using a male and a female anthropomorphic phantom, coupled with the MCNPX (2.7.1) Monte Carlo simulation software, for three different types of soil. The highest CC[HT] values were for the gonads and skin (male) and bone marrow and skin (female). We found no difference for the different types of soil.Artigo IPEN-doc 24444 Estudo do material do eletrodo coletor de uma câmara de extrapolação por simulação de Monte Carlo2017 - VEDOVATO, ULY P.; NEVES, LUCIO P.; SANTOS, WILLIAM S.; BELINATO, WALMIR; CALDAS, LINDA V.E.; PERINI, ANA P.Neste trabalho, a influência de diferentes materiais do eletrodo coletor na resposta de uma câmara de ionização de extrapolação foi avaliada. Esta câmara de ionização foi simulada com o código de Monte Carlo MCNP-4C e foi utilizado o espectro de um feixe padrão de radiodiagnóstico (RQR5). Os diferentes resultados obtidos se devem às interações dos fótons com diferentes materiais do eletrodo coletor, contribuírem com valores diferentes de energias depositadas no volume sensível da câmara de ionização, as quais dependem do número atômico dos materiais avaliados. O material que apresentou menor influência foi o grafite, constituinte original da câmara de ionização.Artigo IPEN-doc 24386 Study of a new glass matrix by thermoluminescent technique for high-dose dosimetry2017 - FERREIRA, P.Z.; CARVALHO, G.S.M.; DANTAS, N.O.; SILVA, A.C.A.; NEVES, L.P.; CALDAS, L.V.E.; CARRERA, B.N.S.; WATANABE, S.; PERINI, A.P.The thermoluminescence technique is widely used for both personal and high-dose dosimetry. In this work, the thermo-luminescence technique was employed to study a new glass matrix, with nominal composition of 20Li2CO3.10Al2O3.30BaO.40B2O3 (mol%), irradiated with different doses in a 60Co radioactive source. The glow curves and the dose-response curve were obtained for radiation doses of 10, 50, 100, 200 and 700 Gy. The results showed that this new glass matrix has potential use in high-dose dosimetry.Artigo IPEN-doc 24242 Evaluation of glasses containing cadmium for high dose dosimetry by the thermoluminescence technique2017 - CARVALHO, G.S.M.; FERREIRA, P.Z.; DANTAS, N.O.; SILVA, A.C.A.; PERINI, A.P.; CALDAS, L.V.E.; CARRERA, B.N.S.; WATANABE, S.; NEVES, L.P.New glass matrices were evaluated for high dose dosimetry by the thermoluminescence technique. Their nominal com-position are 20Li2CO3.10Al2O3.15CdO.55B2O3 and 20Li2CO3.10Al2O3.20CdO.50B2O3 (mol%). The glass matrices were irradiated with different doses: 50, 100, 200, 500, 700 and 900 Gy, and the thermoluminescence emission curves were obtained for each of these values. The results show a great potential of using these matrices in high dose dosime-try.Artigo IPEN-doc 23109 The influence of different 192Ir sources geometries to the energy deposition2016 - SANTOS, W.S.; GONALVES, P.E.; BELINATO, W.; CALDAS, L.V.E.; PERINI, A.P.; NEVES, L.P.In this paper, various simpli cations of the HDR source Varian VariSource Classic model, in which 192Ir as a radionuclide is used, were compared. These simpli cations were carried out by Monte Carlo simulations, using the MCNPX 2.7.0 code. The different sources were compared through a distribution of energy deposition in a water phantom. Our results indicated that small simpli cations will present no in uence on the source response, and the removal of the entire capsule surrounding the radionuclide will present a difference of just 0.53% in the nal response.