Browsing by Author "Castro, Rosa"
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- 99mTc-MAA for Lung Perfusion Scintigraphy: Impact of Counting Method on the Effective Number of Particles Administered and Particle Aggregation Over TimePublication . Costa, Pedro; Cunha, Lídia; Soares, Sofia; Mendes, Ângela; Queiroz, Ana; Nunes, Amélia; Ferreira, Elisabete; Botelho, Elisa; Sousa, Maria C.; Castro, Rosa; Pires, Laucena; João, M. Faria; Metello, Luís F.: 99mTc-MAA (macroaggregates of albumin) is the selected radiopharmaceutical for the Lung Perfusion Scintigraphy. It is retained in lung capillaries by mechanical blockage resulting in local microembolization. Care should be taken concerning not only particle size but also the number of particles administered to patients, particularly those who present with special conditions (pulmonary hypertension, shunt or lung transplant). European Pharmacopoeia only requires the assessment of particle size. This work aims to characterize particle size and particle aggregation of two commercial brands of MAA kits and to compare particle counting methods
- 99mTc-MAA for Lung Perfusion Scintigraphy: Impact of Counting Method on the Effective Number of Particles Administered and Particle Aggregation Over TimePublication . Costa, Pedro; Cunha, Lídia; Soares, Sofia; Mendes, Ângela; Queiroz, A. Isabel; Nunes, Amélia; Ferreira, Elisabete; Botelho, Elisa; Sousa, Conceição; Castro, Rosa; Pires, Laucena; João, M. Faria; Metello, Luís F.Introduction: 99mTc-MAA (macroaggregates of albumin) is the selected radiopharmaceutical for the Lung Perfusion Scintigraphy. It is retained in lung capillaries by mechanical blockage resulting in local microembolization. Care should be taken concerning not only particle size butalso the number of particles administered to patients, particularly those who present with special conditions (pulmonary hypertension, shunt or lung transplant). European Pharmacopoeia only requires the assessment of particle size. This work aims to characterize particle size and particle aggregation of two commercial brands of MAA kits and to compare particle counting methods.
- Acetyl-L-Carnitine Improves Cell BioenergeticsPublication . Cunha, Lídia; Bravo, Joana; Costa, Pedro; Fernandes, Sílvia; Oliveira, Marta; Castro, Rosa; Metello, Luís F.; Summavielle, TeresaIntroduction: Acetyl-L-Carnitine (ALC), a natural occurring compound in all mammalian species, plays a variety of vital functions in the body. The most important are related to mitochondria, namely the transport of fatty acids for energy production through β oxidation and the control of acyl-CoA/CoA ratio. Due to this close interaction with cell bioenergetics, it plays a role in many diseases, especially those related to the mitochondria. We propose to characterize the action of ALC in mitochondrial bioenergetics and functional integrity.
- Estudo do valor da hidratação na qualidade de imagem de uma cintigrafia ósseaPublication . Ferreira, Sara; Silva, José Alexandre; Amorim, Inês; Castro, Rosa; Nery, Jorge; Oliveira, Marta; Sousa, Maria; Cunha, Lídia; Metello, Luís F.A cintigrafia óssea é um método de diagnóstico não invasivo e sensível em detectar lesões ósseas precocemente. Um dos importantes aspectos técnicos a considerar quando se trata da preparação do doente é o nível de hidratação. O objectivo deste estudo centra-se sobre a apreciação do valor de hidratação na qualidade das imagens de uma cintigrafia óssea
- Practical Quality Control: Comparision of Methods on the Quantification of Stationary Phases in Paper and Thin-Layer Chromatographic SystemsPublication . Cunha, Lídia; Folgado, Vítor; Ferreira, Sara; Lourenço, Leonel; Osório, Soraia; Oliveira, Marta; Sousa, Maria; Amorim, Inês; Castro, Rosa; Metello, Luís F.Introduction: Paper and thin layer chromatography methods are frequently used in Classic Nuclear Medicine for the determination of radiochemical purity (RCP) on radiopharmaceutical preparations. An aliquot of the radiopharmaceutical to be tested is spotted at the origin of a chromatographic strip (stationary phase), which in turn is placed in a chromatographic chamber in order to separate and quantify radiochemical species present in the radiopharmaceutical preparation. There are several methods for the RCP measurement, based on the use of equipment as dose calibrators, well scintillation counters, radiochromatografic scanners and gamma cameras. The purpose of this study was to compare these quantification methods for the determination of RCP. Material and Methods: 99mTc-Tetrofosmin and 99mTc-HDP are the radiopharmaceuticals chosen to serve as the basis for this study. For the determination of RCP of 99mTc-Tetrofosmin we used ITLC-SG (2.5 x 10 cm) and 2-butanone (99mTc-tetrofosmin Rf = 0.55, 99mTcO4- Rf = 1.0, other labeled impurities 99mTc-RH RF = 0.0). For the determination of RCP of 99mTc-HDP, Whatman 31ET and acetone was used (99mTc-HDP Rf = 0.0, 99mTcO4- Rf = 1.0, other labeled impurities RF = 0.0). After the development of the solvent front, the strips were allowed to dry and then imaged on the gamma camera (256x256 matrix; zoom 2; LEHR parallel-hole collimator; 5-minute image) and on the radiochromatogram scanner. Then, strips were cut in Rf 0.8 in the case of 99mTc-tetrofosmin and Rf 0.5 in the case of 99mTc-HDP. The resultant pieces were smashed in an assay tube (to minimize the effect of counting geometry) and counted in the dose calibrator and in the well scintillation counter (during 1 minute). The RCP was calculated using the formula: % 99mTc-Complex = [(99mTc-Complex) / (Total amount of 99mTc-labeled species)] x 100. Statistical analysis was done using the test of hypotheses for the difference between means in independent samples. Results:The gamma camera based method demonstrated higher operator-dependency (especially concerning the drawing of the ROIs) and the measures obtained using the dose calibrator are very sensitive to the amount of activity spotted in the chromatographic strip, so the use of a minimum of 3.7 MBq activity is essential to minimize quantification errors. Radiochromatographic scanner and well scintillation counter showed concordant results and demonstrated the higher level of precision. Conclusions: Radiochromatographic scanners and well scintillation counters based methods demonstrate to be the most accurate and less operator-dependant methods.
- Study of the Influence of Patient Hydration in Bone ScintigraphyPublication . Ferreira, Sara; Cunha, Lídia; Osório, Soraia; Matias, Mariana; Lemos, Joana; Vieira, Domingos; Soares, Sofia; Fonseca, Abigaíl; Silva, José Alexandre; Amorim, Inês; Castro, Rosa; Metello, Luís F.The bone scintigraphy is a diagnosis method noninvasive and sensitive in detecting early bone lesions, constituting about 35% of all tests performed in the Service of Nuclear Medicine, of the Hospital of Santo Antonio, in the city of Porto, where the following study took place. One of the important technical details in preparing the patient for this examination is the hydration following the administration of the radiopharmaceutical. The aim of this study focused on assessing the value of hydration on the quality of the image in a bone scintigraphy.