EDUARDO DE LIMA CORREA
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Resumo IPEN-doc 27011 Activimeter response behaviour analysis related to well depth2016 - KUAHARA, LILIAN; CORREA, EDUARDO; POTIENS, MARIA da P.The activimeter, instrument used to radionuclide activity measure, consist primarily of a well type ionization chamber coupled to a special electronic device. Its response, after calibration, is shown in units of the activity quantity (Becquerel or Curie). It also has a special holder designed to accommodate all kinds of syringes and vials containing the radiopharmaceuticals. Many factors influence the response of an activimeter such as the volume of the sample, its position inside the activimeter well and the geometry of the vials. The idea of this study is to find the better position inside the well to get the best activity values, positioning the holder in different profundity, simulating a clinical procedure. The reference activimeter used was the Secondary Standard NPL-CRC radionuclide calibrator, traceable to the National Physical Laboratory (NPL), England, taking as reference the depth of 400 mm. Two other activimeters were tested: Capintec, CRC-15BT model with the depth of 170 mm and one CRC-25R model with depth of 257 mm. They all belong to the Instrument Calibration Laboratory of IPEN, São Paulo, Brazil. The measurements were made using three radioactive check sources: Co-57, Ba-133 and Cs-137. Sources readings were taken at various depths inside the ionization chamber well. The results shown maximum variation of 14.28% for Co-57, 11.27% to Ba-133 and 8.8% to Cs-137. All measurements were compared with those values found for the reference depth in each activimeter. The variation found show the necessity of include this kind of determination in all quality control programs that are applied to an activimeter used by a Nuclear Medicine Service.Artigo IPEN-doc 25107 Influence of the vials radioactive residue in Nuclear Medicine procedure applied to a new “in situ” activimeter calibration methodology2019 - KUAHARA, L.T.; CORREA, E.L.; CARNEIRO, R.C.G.; BEZERRA, R.R.L.; POTIENS, M.P.A.In this study we present a new “in situ” calibration methodology establishment for activimeters – i.e., this equipment calibration can be made at the hospital and/or the nuclear medicine service (NMS) – and also the importance of considering vials radioactive residue when generating the calibration coefficient in terms of activity (NA). For the calibration, two methods are presented here: in the first, 99mTc sample activity (AC) is measured in the NMS. Then it is sent to the Instruments Calibration Laboratory (LCI/IPEN) where the reference activity (AR) is obtained under controlled conditions in a reference vial. After geometry and residue corrections, NA is calculated. In the second method, AR is obtained at the LCI, then 99mTc sample is sent to the hospital/NMS, where AC is measured and NA calculated. Calibration methodologies were applied to three NMS and to four equipment belonging to the radiopharmaceutical production facility (CR) at the Nuclear and Energy Research Institute (IPEN). Both methodologies were tested with and without residual activity corrections under controlled conditions. Variations of up to 4% were obtained.Artigo IPEN-doc 24420 Análise da variação da atividade de uma amostra de 99mTc após diluição com soro fisiológico2017 - KUAHARA, L.T.; CORREA, E.L.; POTIENS, M.P.A.O ativímetro é um equipamento essencial em um serviço de medicina nuclear. Garantir seu bom funcionamento e conhecer os fatores que podem influenciar na sua leitura é fundamental para que a atividade administrada ao paciente esteja correta. Vários fatores podem causar alterações na resposta do ativímetro, como o tipo de recipi- ente, geometria e volume do radioisótopo. O objetivo deste trabalho foi analisar as variações nas medições de 0,5 mL e 1,0 mL de 99mTc puro e diluído em até 2,5 mL de soro fisiológico, em recipientes utilizados em medicina nuclear. Foram encontradas variações de até 4 % nos valores medidos.Resumo IPEN-doc 23261 Influence of the vials radioactive residue in Nuclear Medicine procedure applied to a new “in situ” activimeter calibration methodology2017 - KUAHARA, LILIAN T.; CORREA, EDUARDO; POTIENS, MARIA da P.A.A safe and efficient Nuclear Medicine Services (NMS) performance depends, among other factors, on a complete quality assurance program, mainly in the case of the activity meters. Many elements may influence this equipment response, being the major errors related to vials characteristics, such as volume and geometry, as presented in other studies [1,2]. Correction factors must be applied in order to avoid patient exposure to excessive doses.However, another aspect that should be taken into account is how much radioactive material is lost during the radioisotope labeling, a process that includes many recipient changes.In this study we present the estimated activity lost during 99mTc labeling process and show how important is to add this value to the total activity measured in a new “in situ” calibration procedure, in which the activity meter is not removed from its place of use. For the radioactive residue determination99mTc labeling procedure was reproduced under laboratorial conditions, resulting in losses of up to 40 %. However greater errors are expected in a NMS. Activity meter calibration using two methodologies: the first consists in a direct comparison between the two systems with the same vial (P6-P6 and 10R-10R), and the second is a comparison made using two different vials (P6-10R), with and without geometry and residual activity corrections. A calibration factor of 0.999 was obtained in the reference situation. The same procedure performed without the application of the necessary correction factors resulted in a variation of almost 3 %, which is high considering the test was made under controlled conditions and less residue was left inside vials. The “in situ” calibration procedure worked well and was important to present the need of correction factors application, including the residue activity measurement.Artigo IPEN-doc 21057 Determination of geometry correction factors to different vials used to radiopharmaceutical activity measurements2015 - KUAHARA, LILIAN T.; CORREA, EDUARDO L.; POTIENS, MARIA da P.A.Artigo IPEN-doc 20422 Acceptance test of an activity meter to be used as reference in a calibration methodology establishment2014 - CORREA, EDUARDO L.; KUAHARA, LILIAN T.; POTIENS, MARIA da P.A.Artigo IPEN-doc 19447 Quality control tests of an activity meter to be used as reference for an in situ calibration methodology2013 - CORREA, EDUARDO de L.; KUAHARA, LILIAN T.; POTIENS, MARIA da P.A.Artigo IPEN-doc 19466 Testes de controle de qualidade em calibradores de dose utilizados em laboratórios de pesquisa do IPEN2013 - KUAHARA, LILIAN T.; MARTINS, ELAINE W.; DIAS, CARLA R.; CORREA, EDUARDO de L.; POTIENS, MARIA da P.A.; JUNIOR, AMAURY C.R.