ESS - MN - Comunicações em eventos científicos
Permanent URI for this collection
Browse
Browsing ESS - MN - Comunicações em eventos científicos by Issue Date
Now showing 1 - 10 of 53
Results Per Page
Sort Options
- Parameters optimization of filtered back projection in Myocardial Perfusion Imaging reconstructionPublication . Metelo, Luís Francisco; Cunha, L.; Vieira, Domingos; Fonseca, A.; Tavares, A.; Soares, S.; Amorim, I.; Castro, R.; Abrantes, A. M.; Botelho, M. F.Nowadays, even if it is noticed an increasingly wider use of Iterative Methods (IM), a significant number of NM Departments is still routinely using Filtered Backprojection (FBP) as the method of choice in what concerns image processing in MPI. Several authors recommend the use of same filter parameters, no matter what the patient physical characteristics are.
- 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.
- 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
- Stunning tiroideu: uma abordagem técnica às suas causas, consequências e soluções.Publication . Lemos, Joana; Nunes, André; Cunha, Lídia; Metello, Luís F.Objectivos – Compreender o contributo da Medicina Nuclear num contexto de carcinoma diferenciado da tiróide (CDT). Debater a pertinência da cintigrafia de pesquisa pré-terapêutica com Iodo-131 (131I) na preparação do tratamento com o mesmo radionuclídeo. Entender o fenómeno stunning ou atordoamento tiroideu, as suas causas, consequências e soluções. Apontar e discutir as principais semelhanças e diferenças entre uma cintigrafia de pesquisa pré-terapêutica com 131I e o mesmo estudo mas com Iodo-123 (123I).
- Study of the influence of patient hydration in bone ScintigraphyPublication . Ferreira, S.; Cunha, L.; Fonseca, A.; Vieira, Domingos; Lemos, Joana; Matias, M.; Osorio, S.; Soares, S.; Silva, J. A.; Amorim, M. I.; Castro, R.; Metelo, Luís FranciscoBone Scintigraphy is a noninvasive and very sensitive Nuclear Medicine diagnostic method in detecting early bone lesions. Between the important technical details to consider when dealing with patient preparation there is the hydration level.
- Motion correction software in Myocardial Perfusion Imaging: is it useful?Publication . Cunha, L.; Lamego, J.; Ferreira, S.; Lemos, Joana; Vieira, Domingos; Fonseca, A.; Pires, L.; Neves, D.; João, M. Faria; Pereira, L.; Moreira, A. S.; Metelo, Luís FranciscoMyocardial Perfusion Imaging (MPI) is a very important tool in the assessment of Coronary Artery Disease (CAD) patients 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.
- Determination of the radiochemical purity of 99mTc-Tetrofosmin: comparision between five methodsPublication . Aguiar, Ana; Oliveira, Marta; Teixeira, Dalila; Cunha, Lídia; Metello, Luís F.GOAL: The manufacturing and distribution of strips of instant thin - layer chromatography with silica gel (ITLC - SG) (reference method) is currently discontinued so there is a need for an alternative method f or the determination of radiochemical purity (RCP) of 99m Tc - tetrofosmin. This study aims to compare five alternative methods proposed by the producer to determine the RCP of 99m Tc - tetrofosmin. METHODS: Nineteen vials of tetrofosmin were radiolabelled with 99m Tc and the percentages of the RCP were determined. Five different methods were compared with the standard RCP testing method (ITLC - SG, 2x20 cm): Whatman 3MM (1x10 cm) with acetone and dichloro - methane (method 1); Whatman 3MM (1x1 0 cm) with ethyl acetate (method 2); aluminum oxide - coated plastic thin - layer chromatography (TLC) plate (1x10 cm) and ethanol (method 3); Whatman 3MM (2x20 cm) with acetone and dichloro - methane (method 4); solid - phase extraction method C18 cartridge (meth od 5). RESULTS: The average values of RCP were 95,30% ± 1,28% (method 1), 93,95 ± 0,61% (method 2), 96,85% ± 0,93% (method 3), 92,94% ± 0,99% (method 4) and 96,25% ± 2,57% (method 5) (n=12 each), and 93,15% ± 1,13% for the standard method (n=19). There we re statistical significant differences in the values obtained for methods 1 (P=0,001), 3 (P=0,000) and 5 (P=0,004), and there were no statistical significant differences in the values obtained for methods 2 (P=0,113) and 4 (P=0,327). CONCLUSION: From the results obtained, methods 2 and 4 showed a higher correlation with the standard method. Unlike method 4, method 2 is less time - consuming than the reference method and can overcome the problems associated with the solvent toxicity. The remaining methods (1, 3 and 5) tended to overestimate RCP value compared to the standard method.
- 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 .
- The Use of Annexin-V labeled with 99mTc in the evaluation of cardiotoxicity induced by anthracyclinesPublication . Miranda, Cecília; Cunha, Lídia; Metello, Luís F.The antineoplastic Anthracyclines are effective agents for various tumors, there is a dose-response relationship for these drugs, however, cardiotoxicity limits their therapeutic potential and threaten the cardiac function of patients. The mechanism of the onset of cardiotoxicity is still not clarified, the most common hypothesis is related to the triggering mechanisms of programmed death - apoptosis - that promote various morphological and biochemical changes in cells. A very early stage, there is the exposure of phosphatidylserine, a phospholipid that in healthy cells remains in the inner leaflet of the plasma membrane. This exhibition may be marked through radioactive molecules, as is the case of 99mTcAnnexin V, the Annexin V is an endogenous human protein, distributed intracellularly, with high affinity for phosphatidylserine.
- Cyclotech - contribution to solve the Technetium shortage by using low energy medical cyclotronsPublication . Metello, Luís F.; Gelbart, W.; Benedict, Malcom; Cunha, Lídia; Alves, Francisco; Johnson, Richard R.This paper presents work in progress, to develop an efficient and economic way to directly produce Technetium 99metastable (99mTc) using low-energy cyclotrons. Its importance is well established and relates with the increased global trouble in delivering 99mTc to Nuclear Medicine Departments relying on this radioisotope. Since the present delivery strategy has clearly demonstrated its intrinsic limits, our group decided to follow a distinct approach that uses the broad distribution of the low energy cyclotrons and the accessibility of Molybdenum 100 (100Mo) as the Target material. This is indeed an important issue to consider, since the system here presented, named CYCLOTECH, it is not based on the use of Highly Enriched (or even Low Enriched) Uranium 235 (235U), so entirely complying with the actual international trends and directives concerning the use of this potential highly critical material. The production technique is based on the nuclear reaction 100Mo (p,2n) 99mTc whose production yields have already been documented. Until this moment two Patent requests have already been submitted (the first at the INPI, in Portugal, and the second at the USPTO, in the USA); others are being prepared for submission on a near future. The object of the CYCLOTECH system is to present 99mTc to Nuclear Medicine radiopharmacists in a routine, reliable and efficient manner that, remaining always flexible, entirely blends with established protocols. To facilitate workflow and Radiation Protection measures, it has been developed a Target Station that can be installed on most of the existing PET cyclotrons and that will tolerate up to 400 μA of beam by allowing the beam to strike the Target material at an adequately oblique angle. The Target Station permits the remote and automatic loading and discharge of the Targets from a carriage of 10 Target bodies. On other hand, several methods of Target material deposition and Target substrates are presented. The object was to create a cost effective means of depositing and intermediate the target material thickness (25 - 100μm) with a minimum of loss on a substrate that is able to easily transport the heat associated with high beam currents. Finally, the separation techniques presented are a combination of both physical and column chemistry. The object was to extract and deliver 99mTc in the identical form now in use in radiopharmacies worldwide. In addition, the Target material is recovered and can be recycled.