ANA PAULA PERINI
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Resumo IPEN-doc 26035 Computational dosimetry in a pediatric iCAT procedure using a virtual antropomorphic phantom2018 - NEVES, LUCIO P.; BORGES, ADRIANE; SOARES, MARIA R.; BELINATO, WALMIR; SANTOS, WILLIAM S.; CALDAS, LINDA V.E.; PERINI, ANA P.Artigo IPEN-doc 24788 Estimation of conversion coefficients for absorbed and effective doses for pediatric CT examinations in two different PET/CT scanners2019 - PERINI, ANA P.; SANTOS, WILLIAM S.; NEVES, LUCIO P.; BELINATO, WALMIR; CALDAS, LINDA V.E.Normally, during medical procedures, special attention must be given to pediatric patients when compared to adults. This is specially relevant during procedures involving ionizing radiation, as CT scans, given that children are considerably more sensitive to radiation induced stochastic effects than adults. In order to investigate the radiation doses on radiosensitive organs of pediatric patients, undergoing head, chest and abdomen CT procedures, numerical dosimetry was employed in this work. The novelty is the use of a new set of pediatric virtual anthropomorphic phantoms, coupled with Monte Carlo simulation, to determine the conversion coefficients for absorbed and effective doses. Two CT equipment were simulated, taking into account the main characteristics of those commercially available. The results were converted to conversion coefficients (mGy/100 mA) for several organs and tissues, and the highest values were obtained for the newborn phantom. This numerical approach employed a new and reliable technique for pediatric CT dosimetry.Artigo IPEN-doc 24752 Dose estimate for cone beam CT equipment protocols using Monte Carlo simulation in computational adult anthropomorphic phantoms2019 - SOARES, MARIA R.; SANTOS, WILLIAM S.; NEVES, LUCIO P.; PERINI, ANA P.; BATISTA, WILSON O.G.; BELINATO, WALMIR; MAIA, ANA F.; CALDAS, LINDA V.E.Cone beam computed tomography (CBCT) has become essential for dental diagnoses in the last decade. This is supported by its low cost and low doses, when compared to medical CT. Following this increase in CBCT procedures, it is necessary to ensure the image quality within low radiation doses to the patients. This is an especially difficult challenge in CBCT, given the number of equipment models (more than 50), radiographic techniques that may be employed, and technical information not available to the users by the manufacturers. The objective of this study was to estimate the cancer risk, effective and absorbed doses in tissues and organs for CBCT protocols intended for dental use. Monte Carlo (MC) simulations were used to estimate these quantities in tissues and organs with radiological importance, as those suggested by the International Commission of Radiological Protection (ICPR) report ICRP 103. Five different fields of view (FOV) were simulated to i-Cat Classic CBCT, using the MCNPX code. The virtual anthropomorphic phantoms FASH3 (Female Adult MeSH) and MASH3 (Male Adult MeSH) were also used. The effective dose estimative was in the range 75.15–142.20 μSv. The largest contribution to the effective dose was from the salivary glands (17%), thyroid (27%) and remainder tissues (28%). The results of this work showed that the effective and absorbed doses in tissues/organs vary according to the FOV, exposure parameters, and the positioning of the beam, relative to the radiosensitive organs. Furthermore, for the same exposure conditions, women can exceed the total risk of cancer by 26–34%, when compared to men.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 24712 Monte Carlo dosimetric evaluation in PET exams for patients with different BMI and heights2018 - BELINATO, WALMIR; SILVA, ROGERIO M.V.; PERINI, ANA P.; NEVES, LUCIO P.; SANTOS, CARLA J.; SOUZA, DIVANIZIA N.; SANTOS, WILLIAM S.In recent years, positron emission tomography (PET), associated with multi-detector computed tomography (MDCT), has become a diagnostic technique widely disseminated to evaluate various malignant tumors and other diseases. However, during PET/CT examinations, the doses of ionizing radiation experienced by the internal organs of the patients due to 18F are unknown, and may be substantial. The aim of this study was to determine a set of S values derived from the 18F-FDG and to use them to determine the absorbed and effective doses of 8 different virtual anthropomorphic phantoms (4 of each gender). These phantoms have different Body Mass Index (BMI), to represent different anatomical characteristics of patients examined in PET. The results of the S values were calculated using the MCNPX (2.7.0) Monte Carlo code. These results were compared to the ICRP 106 reference values, obtained with mathematical anthropomorphic phantoms (MIRD model). Our results of the S values were higher than those obtained and presented at the ICRP 106, mainly due to the differences between the phantoms. The differences between the relative distances of the organs and the chemical and physical characteristics of the phantoms used in this study, in relation to mathematical model, reflected the use of a detailed set of phantoms. Therefore, the results presented in this study provide accurate and reliable data for internal dose calculations for patients undergoing PET examinations.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 23760 Estimate of S-values for children due to six positrons emitting radionuclides used in PET examinations2016 - BELINATO, W.; SANTOS, W.S.; PERINI, A.P.; CALDAS, L.V.E.; NEVES, L.P.; SOUZA, D.N.Resumo IPEN-doc 22632 Determinação de fatores de conversão das doses em Tomografia Computadorizada odontológica de feixe cônico utilizando método de Monte Carlo2015 - BELINATO, WALMIR; SANTOS, WILLIAN S.; NEVES, LUCIO P.; PERINI, ANA P.; CALDAS, LINDA V.; SOUZA, DIVANIZIA N.Resumo IPEN-doc 21379 A new cubic phantom for PET/CT dosimetry: experimental and Monte Carlo characterization2015 - BELINATO, WALMIR; SILVA, ROGERIO M.V.; SANTOS, WILLIAM S.; PERINI, ANA P.; NEVES, LUCIO P.; CALDAS, LINDA V.E.; SOUZA, DIVANIZIA N.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.