LUCAS RODRIGUES DOS SANTOS

LUCAS RODRIGUES DOS SANTOS

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Tandem KAP meters calibration parameters by Monte Carlo Simulation using reference RQR radiation qualities
2016 - POTIENS JUNIOR, ADEMAR; COSTA, NATHALIA; CORREA, EDUARDO; SANTOS, LUCAS; VIVOLO, VITOR; POTIENS, MARIA da P.
The Kerma-area product quantity can be obtained by measurements carried out with a kerma-area product meter (KAP) with a plane-parallel transmission ionization chamber mounted on the X ray system. It is the integral of the air kerma over the area of the X ray beam in a plane perpendicular to the beam axis. This quantity has been important to establish the diagnostic reference levels (DRLs) all over the word. In this work the MCNP5 code was used to calculate the imparted energy in the air cavity of KAP meter and the spatial distribution of the air collision kerma in entrance plan of the KAP meter. From these data, the air kerma-area product (KAP) and the calibration coefficient for the KAP meter were calculated and compared with those obtained experimentally. The X-ray tube was easily modelled as well the complete tandem calibration set up was possible. The spectra of the diagnostic radiology RQR reference qualities measured were used as a source definition in the input card for the Monte Carlo simulation. The clinical KAP meter calibration coefficients were obtained experimentally and by Monte Carlo simulation. The differences between those values were about 2%, except for RQR 10 (5.45%). The uncertainties in Monte Carlo simulation were less than 0.5% in all cases and the FOM (Figure of Merit) was constant for a number of histories of 1 million.
Evaluation of the behavior of a 180cc ionization chamber under different environmental conditions
2019 - SILVA, E.; SANTOS, L.R.; ASSEMANY, L.P.F.; POTIENS, M.P.A.
The use of ionizing radiation for medical purposes has been a major advance for society due to the numerous possibilities of use for the treatment and diagnosis of diseases. On the other hand, knowledge about the damage caused by the biological effects of ionizing radiation requires continuous improvement of diagnostic radiology quality control. Radiation detector equipment is used to measure radiation levels emitted from natural or artificial sources. For convenience and accuracy, among the most widely used detectors are ionization chambers. Especially outdoors, weather factors can affect the behavior of these detectors at the time of measurement, but Brazilian law recommends only calibrating these measuring instruments in a traceable laboratory every two years to ensure their reliability. The objective of this work was to evaluate the performance of an ionization chamber used in radioprotection measurements in diagnostic radiology equipment, considering climatic variations in different regions of Brazil. For this, a system was developed to simulate the environmental conditions found for the temperature and humidity parameters at the moment of the clinical measurements, allowing to estimate the influence of these factors on the obtained values.
Evaluation of the performance of radioprotection ionization chambers used in radiometric survey of radiology clinical systems
2019 - SILVA, E.; SANTOS, L.R.; ASSEMANY, L.P.F.; POTIENS, M.P.A.
Evaluation of an extrapolation chamber for dosimetry in computed tomography beams using Monte Carlo code (MCNP5)
2018 - CASTRO, MAYSA C.; SILVA, NATALIA F.; SANTOS, LUCAS R.; CINTRA, FELIPE B.; CALDAS, LINDA V.E.
Filtration influence in a constant potential X-ray machine peak voltage measurements
2017 - SANTOS, L.R.; VIVOLO, V.; NAVARRO, M.V.T.; XAVIER, M.; POTIENS, M.P.A.
This work shows the peak voltage measurements for several beam filtrations used in diagnostic radiology, using two types of non-invasive detectors; a voltage meter and a high-resolution spectrometer. The technique chosen for the voltage peak measurements with the spectrometer was the endpoint. The results were compared to the measured ones and showed good similarity to the nominal values. However the voltage meter detector used in this work pre-sented errors for heavier filtrations.
Desenvolvimento de um protocolo de calibração utilizando espectrometria e simulação matemática, em feixes padrões de raios x
2017 - SANTOS, LUCAS R. dos
A calibração, por definição, é o processo pelo qual se estabelece uma relação entre valores de medição de um padrão, com as suas respectivas incertezas, e as indicações com as incertezas associadas do instrumento de medição a ser calibrado. Um protocolo de calibração descreve a metodologia a ser aplicada em um processo de calibração. O método escolhido para a obtenção deste protocolo foi o da espectrometria de feixe de raios X associada à simulação pelo método de Monte Carlo, fundamentado no fato de que ambos são considerados métodos absolutos na determinação de parâmetros de feixes de radiação. Neste trabalho foi utilizado o método de Monte Carlo utilizado para obter a função resposta do detector utilizada para a correção dos espectros obtidos do feixe primário de radiação X; deste modo foram calculadas as taxas de kerma destes feixes e comparadas aos valores obtidos com as câmaras de ionização padrão secundário do Laboratório de Calibração de Instrumentos do IPEN (LCI/IPEN). Foram obtidos os coeficientes de calibração para o sistema padrão com diferenças em relação ao fornecido pelo laboratório primário entre 1,3% e 15,3%. Os resultados obtidos indicaram a viabilidade do estabelecimento deste protocolo de calibração utilizando a espectrometria como padrão de referência, com incertezas relativas de 0,62% para k=1. As incertezas associadas ao método proposto foram satisfatórias, para um laboratório padrão secundário e comparáveis a um laboratório primário.
Mammography calibration qualities establishment in a Mo-Mo clinical system
2016 - CORREA, E.L.; SANTOS, L.R. dos; VIVOLO, V.; POTIENS, M.P.A.
In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained.
Comparison of a KAP meter and a PDC behaviour using mathematical simulation in reference diagnostic radiology qualities
2014 - POTIENS JUNIOR, A.J.; COSTA, N.A.; SANTOS, L.R.; CORREA, E.L.; VIVOLO, V.; POTIENS, M.P.A.
Mammography calibration qualities establishment in a Mo-Mo clinical system
2015 - CORREA, E.L.; SANTOS, L.R. dos; VIVOLO, V.; POTIENS, M.P.A.
Evaluation of a measurements system for uranium electrodeposition control to radiopharmaceuticals production
2015 - MADI FILHO, TUFIC; SALIBA SILVA, ADONIS M.; CARDENAS, JOSE P.N.; PEREIRA, MARIA da C.C.; LOPES, VALDIR M.; SILVA, ALEXANDRE P.; SANTOS, DIOGO F.; PURGATO, RAFAEL T.; AREDES, VITOR O.; FIGUEREDO, ANDERSON L.; SANTOS, LUCAS R. dos; SANTOS, BRIANNA dos S.; CORREA, EDUARDO L.