LUCIO PEREIRA NEVES
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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.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.Artigo IPEN-doc 23524 Estimate of S-values for children due to six positron emitting radionuclides used in PET examinations2017 - BELINATO, WALMIR; SANTOS, WILLIAM S.; PERINI, ANA P.; NEVES, LUCIO P.; CALDAS, LINDA V.E.; SOUZA, DIVANIZIA N.Positron emission tomography (PET) has revolutionized the diagnosis of cancer since its conception. When combined with computed tomography (CT), PET/CT performed in children produces highly accurate diagnoses from images of regions affected by malignant tumors. Considering the high risk to children when exposed to ionizing radiation, a dosimetric study for PET/CT procedures is necessary. Specific absorbed fractions (SAF) were determined for monoenergetic photons and positrons, as well as the S-values for six positron emitting radionuclides (11C, 13N, 18F, 68Ga, 82Rb, 15O), and 22 source organs. The study was performed for six pediatric anthropomorphic hybrid models, including the newborn and 1 year hermaphrodite, 5 and 10-year-old male and female, using the Monte Carlo N-Particle eXtended code (MCNPX, version 2.7.0). The results of the SAF in source organs and S-values for all organs showed to be inversely related to the age of the phantoms, which includes the variation of body weight. The results also showed that radionuclides with higher energy peak emission produces larger auto absorbed S-values due to local dose deposition by positron decay. The S-values for the source organs are considerably larger due to the interaction of tissue with non-penetrating particles (electrons and positrons) and present a linear relationship with the phantom body masses. The results of the Svalues determined for positron-emitting radionuclides can be used to assess the radiation dose delivered to pediatric patients subjected to PET examination in clinical settings. The novelty of this work is associated with the determination of auto absorbed S-values, in six new pediatric virtual anthropomorphic phantoms, for six emitting positrons, commonly employed in PET exams.Artigo IPEN-doc 21282 Exposures in interventional radiology using Monte Carlo simulation coupled with virtual anthropomorphic phantoms2015 - SANTOS, WILLIAM S.; NEVES, LUCIO P.; PETRINI, ANA P.; BELINATO, WALMIR; CALDAS, LINDA V.E.; CARVALHO JUNIOR, ALBERICO B.; MAIA, ANA F.Artigo IPEN-doc 21281 Evaluation of the medical and occupational shielding in cerebral angiography using Monte Carlo simulation and virtual anthropomorphic phantoms2015 - SANTOS, WILLIAM S.; NEVES, LUCIO P.; PERINI, ANA P.; CALDAS, LINDA V.E.; MAIA, ANA F.Artigo IPEN-doc 20265 Development and characterization of a graphite-walled ionization chamber as a reference dosimeter for sup(60)Co beams2014 - PERINI, ANA P.; NEVES, LUCIO P.; CALDAS, LINDA V.E.Artigo IPEN-doc 20263 Dosimetric study of a brachytherapy treatment of esophagus with Brazilian sup(192)Ir sources using an anthropomorphic phantom2014 - NEVES, LUCIO P.; SANTOS, WILLIAM S.; GORSKI, RONAN; PERINI, ANA P.; MAIA, ANA F.; CALDAS, LINDA V.E.; ORENGO, GILBERTOSeveral radioisotopes are produced at Instituto de Pesquisas Energéticas e Nucleares for the use in medical treatments, including the activation of 192Ir sources. These sources are suitable for brachytherapy treatments, due to their low or high activity, depending on the concentration of 192Ir, easiness to manufacture, small size, stable daughter products and the possibility of re-utilization. They may be used for the treatment of prostate, cervix, head and neck, skin, breast, gallbladder, uterus, vagina, lung, rectum, and eye cancer treatment. In this work, the use of some 192Ir sources was studied for the treatment of esophagus cancer, especially the dose determination of important structures, such as those on the mediastinum. This was carried out utilizing a FASH anthropomorphic phantom and the MCNP5 Monte Carlo code to transport the radiation through matter. It was possible to observe that the doses at lungs, breast, esophagus, thyroid and heart were the highest, which was expected due to their proximity to the source. Therefore, the data are useful to assess the representative dose specific to brachytherapy treatments on the esophagus for radiation protection purposes.
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