NATALIA FIORINI DA SILVA

NATALIA FIORINI DA SILVA

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Testing an extrapolation chamber in computed tomography standard beams
2018 - CASTRO, M.C.; SILVA, N.F.; CALDAS, L.V.E.
The computed tomography (CT) is responsible for the highest dose values to the patients. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. In order to search for a CT primary standard, an extrapolation ionization chamber built at the Calibration Laboratory (LCI) of the Instituto de Pesquisas Energéticas e Nucleares (IPEN), was tested in this work. The results showed to be within the international recommended limits.
Construction of the TH-GEM detector components for metrology of low energy ionizing radiation
2018 - SILVA, N.F.; SILVA, T.F.; CASTRO, M.C.; LUZ, H.N. da; CALDAS, L.V.E.
The Gas Electron Multiplier (GEM) detector was originally proposed as a position sensitive detector to determine trajectories of particles prevenient from high-energy collisions. In order to study the potential of TH-GEM type detectors in dosimetric applications for low energy X-rays, specifically for the mammography standard qualities, it was proposed to construct a prototype with characteristics suitable for such use. In this work the general, structural and material parameters applicable to the necessary conditions were defined, establishing the process of construction of the components of a prototype.
Comparação entre duas câmaras de ionização do tipo lápis com comprimento de volume sensível de 30 cm
2017 - CASTRO, M.C.; XAVIER, M.; SILVA, N.F.; CALDAS, L.V.E.
A tomografia computadorizada (CT) vem crescendo devido aos avanços da tecnologia dos equipamentos, proporci-onando uma dose maior no paciente, em relação aos demais exames de radiodiagnóstico, levando a uma preocupa-ção com os pacientes. A dosimetria em CT é realizada com uma câmara de ionização do tipo lápis com comprimen-to de volume sensível de 10 cm. Os estudos têm mostrado a subestimação dos valores de dose. Foram desenvolvidas neste trabalho duas câmaras de ionização com comprimentos de volume sensível de 30 cm, que foram submetidas aos testes principais de caracterização, obtendo-se resultados dentro dos limites recomendáveis internacionalmente. Palavras-chave: Dosimetria, tomografia computadorizada, câmara de ionização especial.
Development and tests of a 30cmpencil-type ionization chamber for dosimetry in standard and clinical CT beams
2017 - CASTRO, M.C.; SILVA, N.F.; XAVIER, M.; ANDRADE, M.E.A.; KHOURY, H.J.; CALDAS, L.V.E.
The use of computed tomography (CT) for imaging procedures is growing due to advances in the CT equipment technology. To perform the dosimetry inCT beams, the most widely used instrument is the pencil type ionization chamber with a sensitive volume length of 100 mm; however, some studies have shown that this dosimeter has underestimated the dose values. Therefore, in this study an ionization chamber with sensitive volume length of 300mmwas developed at IPEN. The characterization of this chamber was performed, and the results were obtained within the international recommended limits. As an application, the developed ionization chamber was tested in clinical beams of two different hospitals.
Characterization of a free air ionization chamber for low energy X-rays
2016 - SILVA, NATALIA F. DA; XAVIER, M.; VIVOLO, V.; CALDAS, L.V.E.
Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition.