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- Actual Trends in Nuclear MedicinePublication . Vieira, Domingos; Lemos, Joana; Ferreira, Sara; Metello, Luís F.
- Actualities on Nuclear Medicine Applications in Sports MedicinePublication . Fonseca, Abigaíl; Soares, Sofia; Cunha, Lídia; Metello, Luís F.Aims: This paper aims to address some of the main possible applications of actual Nuclear Medicine Imaging techniques and methodologies in the specific context of Sports Medicine, namely in two critical systems: musculoskeletal and cardiovascular. Discussion: At the musculoskeletal level, bone scintigraphy techniques proved to be a mean of diagnosis of functional orientation and high sensibility compared with other morphological imaging techniques in the detection and temporal evaluation of pathological situations, for instance allowing the acquisition of information of great relevance in athletes with stress fractures. On the other hand, infection/inflammation studies might be of an important added value to characterize specific situations, early diagnose of potential critical issues – so giving opportunity to precise, complete and fast solutions – while allowing the evaluation and eventual optimization of training programs. At cardiovascular system level, Nuclear Medicine had proved to be crucial in differential diagnosis between cardiac hypertrophy secondary to physical activity (the so called "athlete's heart") and hypertrophic cardiomyopathy, in the diagnosis and prognosis of changes in cardiac function in athletes, as well as in direct - and non-invasive - in vivo visualization of sympathetic cardiac innervation, something that seems to take more and more importance nowadays, namely in order to try to avoid sudden death episodes at intense physical effort. Also the clinical application of Positron Emission Tomography (PET) has becoming more and more widely recognized as promising. Conclusions: It has been concluded that Nuclear Medicine can become an important application in Sports Medicine. Its well established capabilities to early detection of processes involving functional properties allied to its high sensibility and the actual technical possibilities (namely those related with hybrid imaging, that allows to add information provided by high resolution morphological imaging techniques, such as CT and/or MRI) make it a powerful diagnostic tool, claiming to be used on an each day higher range of clinical applications related with all levels of sport activities. Since the improvements at equipment characteristics and detection levels allows the use of smaller and smaller doses, so minimizing radiation exposure it is believed by the authors that the increase of the use of NM tools in the Sports Medicine area should be considered.
- Analysing the usefulness of motion correction software in myocardial perfusion imagingPublication . Cunha, Lídia; Lamego, Juliana; Ferreira, Sara; Lemos, Joana; Vieira, Domingos; Metello, Luís F.Introduction Myocardial Perfusion Imaging (MPI) is a very important tool in the assessment of Coronary Artery Disease ( CAD ) patient s and worldwide data demonstrate an increasingly wider use and clinical acceptance. Nevertheless, it is a complex process and it is quite vulnerable concerning the amount and type of possible artefacts, some of them affecting seriously the overall quality and the clinical utility of the obtained data. One of the most in convenient artefacts , but relatively frequent ( 20% of the cases ) , is relate d with patient motion during image acquisition . Mostly, in those situations, specific data is evaluated and a decisi on is made between A) accept the results as they are , consider ing that t he “noise” so introduced does not affect too seriously the final clinical information, or B) to repeat the acquisition process . Another possib ility could be to use the “ Motion Correcti on Software” provided within the software package included in any actual gamma camera. The aim of this study is to compare the quality of the final images , obtained after the application of motion correction software and after the repetition of image acqui sition. Material and Methods Thirty cases of MPI affected by Motion Artefacts and repeated , were used. A group of three, independent (blinded for the differences of origin) expert Nuclear Medicine Clinicians had been invited to evaluate the 30 sets of thre e images - one set for each patient - being ( A) original image , motion uncorrected , (B) original image, motion corrected, and (C) second acquisition image, without motion . The results so obtained were statistically analysed . Results and Conclusion Results obtained demonstrate that the use of the Motion Correction Software is useful essentiall y if the amplitude of movement is not too important (with this specific quantification found hard to define precisely , due to discrepancies between clinicians and other factors , namely between one to another brand); when that is not the case and the amplitude of movement is too important , the n the percentage of agreement between clinicians is much higher and the repetition of the examination is unanimously considered ind ispensable.
- Cellulose‑based hydrogel on quantum dots with molecularly imprinted polymers for the detection of CA19‑9 protein cancer biomarkerPublication . Piloto, Ana Margarida L.; Ribeiro, David S.M.; Rodrigues, S. Sofia M.; Santos, João L.M.; Sampaio, Paula; Sales, Maria Goreti FerreiraMolecularly imprinted polymers (MIPs), were successfully assembled around quantum dots (QDs), for the detection of the carbohydrate antigen CA19-9, a biomarker associated with pancreatic cancer (PC). The imprinted materials MIP@QDs were incorporated within cellulose hydrogels and designated as imprinted hydrogels (iHGs). The concept is to use MIPs which function as the biorecognition elements, conjugated to QDs as the sensing system. The fluorescence quenching of the iHGs occurred with increasing concentrations of CA19-9, showing linearity in the range 2.76 × 10−2 – 5.23 × 102 U/ml, in a 1000-fold diluted human serum. The iHGs show a linear response below the cutoff values for pancreatic cancer diagnosis (< 23 U/ml), a limit of detection of 1.58 × 10−3 U/ml and an imprinting factor (IF) of 1.76. Moreover, they exhibit stability and selectivity towards CA19-9, when compared with the non-imprinted controls, here designated as non-imprinted hydrogels (non-iHGs). In conclusion, this work demonstrates that the conjugation of MIPs to QDs increases the sensitivity and specificity of the developed sensing system for optical detection methods within clinical significance ranges. This fact shows potential for the iHGs to be applied as a sensitive, low-cost format for point-of-care tests (PoCTs).
- Comparative study between two distinct methods for attenuation correction and the use of no-attenuation correction for the assessment of relative uptake of 99mTc-DMSA on pediatric patientsPublication . Nogueira, Fábio; Lemos, Joana; Fonseca, Abigaíl; Cunha, Lídia; Metello, Luís F.Although relative uptake values aren’t the most important objective of a 99mTc-DMSA scan, they are important quantitative information. In most of the dynamic renal scintigraphies attenuation correction is essential if one wants to obtain a reliable result of the quantification process. Although in DMSA scans the absent of significant background and the lesser attenuation in pediatric patients, makes that this attenuation correction techniques are actually not applied. The geometric mean is the most common method, but that includes the acquisition of an anterior (extra) projection, which it is not acquired by a large number of NM departments. This method and the attenuation factors proposed by Tonnesen will be correlated with the absence of attenuation correction procedures. Material and Methods: Images from 20 individuals (aged 3 years +/- 2) were used and the two attenuation correction methods applied. The mean time of acquisition (time post DMSA administration) was 3.5 hours +/- 0.8h. The absence of attenuation correction showed a good correlation with both attenuation methods (r=0.73 +/- 0.11) and the mean difference verified on the uptake values between the different methods were 4 +/- 3. The correlation was higher when the age was lower. The attenuation correction methods correlation was higher between them two than with the “no attenuation correction” method (r=0.82 +/- 0.8), and the mean differences of the uptake values were 2 +/- 2. Conclusion: The decision of not doing any kind of attenuation correction method can be justified by the minor differences verified on the relative kidney uptake values. Nevertheless, if it is recognized that there is a need for an accurate value of the relative kidney uptake, then an attenuation correction method should be used. Attenuation correction factors proposed by Tonnesen can be easily implemented and so become a practical and easy to implement alternative, namely when the anterior projection - needed for the geometric mean methodology – is not acquired.
- Da Luz à Imagiologia MédicaPublication . Costa, PedroÂmbito: Palestra a convite do Departamento de Física da Universidade de Trás-os-Montes e Alto Douro (ECT - UTAD) Contexto: VII Fórum Física e Sociedade
- Desafios para a formação nas circunstâncias sociolaborais do Norte de PortugalPublication . Rothes, Luís
- Efeitos Biológicos das Radiações IonizantesPublication . Lemos, Joana; Metello, Luís F.
- Evaluation of 99mTc-Sestamibi as a potential tool to investigate PgP activity in inflammationPublication . Costa, Pedro; Cunha, Lídia; Bravo, Joana; Alves, Cecília J.; Summavielle, Teresa; Metello, Luís F.In the XXI Century’s Society the scientific investigation process has been rowing steadily, and the field of the pharmaceutical research is one of the most enthusiastic and relevant. Here, it is very important to correlate bserved functional alterations with possibly modified drug bio distribution patterns. Cancer, inflammation and infection are processes that induce many olecular intermediates like cytokines, chemokines and other chemical complexes that an alter the pharmacokinetics of many drugs. One cause of such changes is hought to be the modulator action of these complexes in the P-Glycoprotein activity, because they can act like inducers/inhibitors of MDR-1 expression. This protein results from the expression of MDR-1 gene, and acts as an ATP energy-dependent efflux pump, withtheir substrates including many drugs, like antiretrovirals, anticancers, anti-infectives, immunosuppressants, steroids or opioids. Because of the lack of methods to provide helpful information in he investigation of in vivo molecular changes in Pgp activity during fection/infl ammation processes, and its value in the explanation of the altered drug harmacokinetic, this paper want to evaluate the potential utility of 99m Tc-Sestamibi scintigraphy during this kind of health sciences investigation. Although the aim is indeed to create a technique to the in vivo study of Pgp activity, this preliminary Project only reaches the in vitro study phase, assumed as the first step in a n evaluation period for a new tool development. Materials and Methods: For that reason , we are performing in vitro studies of influx and efflux of 99m Tc - Sestamibi ( that is a substrate of Pgp) in hepatocytes cell line (HepG2). We are interested in clarify the cellular behavior of this radiopharmaceutical in Lipopolysaccharide(LPS) stimulated cells ( well known in vitro model of inflammation) to possibly approve this methodology. To validate the results, the Pgp expression will be finally evaluated using Western Blot technique. Results: Up to this moment , we still don’t have the final results, but we have already enough data to let us believe that LPS stimulation induce a downregulation of MDR - 1, and consequently Pgp, which could conduce to a prolonged retention of 99m Tc - Sestamibi in the inflamed cells . Conclusions: If and when this methodology demonstrate the promising results we expect, one will be able to con clude that Nuclear Medicine is an important tool to help evidence based research also on this specific field .
- As garantias dos contribuintes perante a administração fiscal no âmbito do processo tributárioPublication . Campos Amorim, JoséPara garantir a tutela jurisdicional efetiva dos direitos e interesses dos contribuintes, o legislador fiscal português institui um conjunto de meios de defesa nas diversas fases do procedimento e processo tributário. Deste conjunto de instrumentos destacam-se as garantias de natureza administrativa e jurisdicional destinadas a assegurar a defesa do contribuinte perante ilegalidades praticadas pela administração fiscal. Sucede que o sistema fiscal não está suficientemente preparado para fazer às diversas questões colocadas pelos contribuintes, o que provoca situações de maior contencioso tributário, que se arrastam durante anos na administração fiscal e nos tribunais tributários. A solução poderá passar por uma simplificação do sistema fiscal, uma desburocratização da administração fiscal e uma maior celeridade dos tribunais tributários.
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