Imaging in neurological and vascular brain diseases (SPECT and SPECT/CT)

Since the first in vivo studies of cerebral function with radionuclides by Ingvar and Lassen, nuclear medicine (NM) brain applications have evolved dramatically, with marked improvements in both methods and tracers. Consequently it is now possible to assess not only cerebral blood flow and energy metabolism but also neurotransmission. Planar functional imaging was soon substituted by single-photon emission computed tomography (SPECT) and positron emission tomography (PET); it now has limited application in brain imaging, being reserved for the assessment of brain death

Exploring the chemical properties of elementary actinide species in the gas phase

Tese de doutoramento, Química (Química-Física), Universidade de Lisboa, Faculdade de Ciências, 2015Gas-phase ion chemistry studies were conducted to search for new elementary actinide (An) species and reactions and to enhance the fundamental understanding of these elements. In the gas phase, with the absence of external perturbations (solvents), physical and chemical properties of elementary actinide species were better studied and relationships between electronic structure, reactivity and energetics established. The role of the 5f electrons and the covalency in these heavy elements were important aspects examined. Most of the studies were performed in parallel with theoretical calculations (through international collaborations), which were essential for complementing the understanding of actinide chemistry. The studies were performed with the use of mass spectrometry techniques, namely Laser Ionization Fourier Transform Ion Cyclotron Resonance (LI-FT-ICR-MS) and Electrospray Ionization Quadrupole Ion Trap (ESI-QIT-MS). The use of these ion traps were very effective for the ion/molecule reaction studies, enabling to perform complex sequences of ion manipulation and obtaining kinetic and mechanistic information. New actinide species and processes were identified, with the actinyl ions, AnO2+/2+, being the highlight of the work: oxo-exchange with water and methanol; addition reactions of water and oxygen to actinyl ions, with a focus in the formation of superoxide uranyl(VI) ions from uranyl(V); synthesis of sulfur “analogues” of actinyls from reactions of An+/2+ ions with COS; determination of the effective charge density of U in uranyl(VI), comparable to that of the late trivalent lanthanides, from the dissociation of bimetallic clusters; evaluation of III/IV redox stabilities of lanthanides and actinides by measurement of hydrolysis rates for MO(NO3)3- species; and coordination studies of biologically relevant ligands, amino acids in particular, that allowed establishing trends of relative stabilities/affinities towards the actinyl ions.Foram efetuados estudos de química de iões em fase gasosa com o objetivo de obter novas espécies e reações de actinídeos (An) e ampliar o conhecimento destes elementos a nível fundamental. Devido à ausência de fatores externos na fase gasosa, nomeadamente solventes, é possível realizar estudos mais precisos das propriedades físicas e químicas de espécies com actinídeos e estabelecer relações entre reatividade, energética e estrutura eletrónica. O papel dos eletrões 5f e a covalência neste tipo de elementos foram dois aspetos importantes abordados. A parte experimental foi realizada em simultâneo com cálculos teóricos, através de colaborações internacionais, que foram essenciais uma vez que permitiram complementar o conhecimento da química dos actinídeos. Recorreu-se ao uso de técnicas de espectrometria de massa, Ionização Laser/Ressonância Ciclotrónica de Iões com Transformada de Fourier (LI-FT-ICR-MS) e Ionização por Eletronebulização/Trapa de Iões Quadrupolar (ESI-QIT-MS). As trapas de iões utilizadas foram bastante vantajosas no estudo de reações ião/molécula, permitindo realizar sequências complexas de manipulação de iões e estudos cinéticos e mecanísticos. Foram identificadas novas espécies e processos envolvendo actinídeos, em que os iões actinilos foram o alvo principal do estudo: oxo-permuta com água e metanol; adição de água e oxigénio molecular a iões actinilos, em que a formação de iões superóxidos de uranilo(VI) partindo de uranilo(V) foi relevante; síntese de espécies análogas de actinilos com enxofre, partido de reações de iões An+/2+ com COS; determinação da carga efetiva do U no uranilo(VI), a qual se verificou ser comparável à dos iões lantanídeos trivalentes, através da dissociação de agregados bimetálicos; avaliação de estabilidades redox dos estados III/IV de lantanídeos e actinídeos estimadas através de reações de hidrólise de espécies MO(NO3)3-; e estudos de coordenação de ligandos aminoácidos com iões actinilos, onde ordens de estabilidade/afinidade foram estimadas.Fundação para a Ciência e a Tecnologia (FCT), SFRH/BD/70475/201

Performing PET/CT studies: do they create anxiety?

Introduction: Anxiety is a common problem in primary care and specialty medical settings. Treating an anxious patient takes more time and adds stress to staff. Unrecognised anxiety may lead to exam repetition, image artifacts and hinder the scan performance. Reducing patient anxiety at the onset is probably the most useful means of minimizing artifactual FDG uptake, both fat brown and skeletal muscle uptake, as well patient movement and claustrophobia. The aim of the study was to examine the effects of information giving on the anxiety levels of patients who are to undergo a PET/CT and whether the patient experience is enhanced with the creation of a guideline. Methodology: Two hundred and thirty two patients were given two questionnaires before and after the procedure to determine their prior knowledge, concerns, expectations and experiences about the study. Verbal information was given by one of the technologists after the completion of the first questionnaire. Results: Our results show that the main causes of anxiety in patients who are having a PET/CT is the fear of the procedure itself, and fear of the results. The patients who suffered from greater anxiety were those who were scanned during the initial stage of a disease. No significant differences were found between the anxiety levels pre procedural and post procedural. Findings with regard to satisfaction show us that the amount of information given before the procedure does not change the anxiety levels and therefore, does not influence patient satisfaction. Conclusions: The performance of a PET/CT scan is an important and statistically generator of anxiety. PET/CT patients are often poorly informed and present with a range of anxieties that may ultimately affect examination quality. The creation of a guideline may reduce the stress of not knowing what will happen, the anxiety created and may increase their satisfaction in the experience of having a PET/CT scan

Inovação social através do comércio justo : o caso de "Probanano - sustentabilidade do sector bananeiro como forma de contribuir para a redução da pobreza na Região de Piura"

Mestrado em Ciências EmpresariaisA presente dissertação tem como objetivo analisar o papel que a inovação social pode exercer no desenvolvimento sustentável através da implementação do comércio justo. O estudo incide sobre um projeto de investimento e inovação social intitulado "Probanano - sustentabilidade do sector bananeiro como forma de contribuir para a redução da pobreza na região de Piura". A ONG - Oikos iniciou este projeto em 2012 no Perú e prevê-se a sua conclusão em 2016. O objectivo é melhorar a qualidade de vida e reduzir a pobreza dos produtores, trabalhadores e comunidades da região de Piura através do desenvolvimento sustentável do sector bananeiro. Com este projecto serão beneficiados 19.000 pequenos agricultores, 24.400 trabalhadores, 36.600 pessoas ligadas indiretamente à indústria da produção de banana e 26 técnicos e funcionários de autoridades municipais e regionais. Apesar de ser um projeto que ainda não está concluído a sua análise já nos permite retirar algumas conclusões, tais como: as práticas de Comércio Justo são inovações sociais e, após a discussão conduzida no Estudo de caso, pudemos verificar que, retornam resultados positivos tangentes às condições ambientais e sociais daqueles que se inserem nesse sistema. As inovações sociais não excluem a necessidade de resultados económicos que são fundamentais para sustentabilidade das instituições. Portanto, este estudo de caso teve como objetivo investigar se o projeto é um caso de inovação social, como forma de alcançar o desenvolvimento sustentável da região.This thesis aims to analyze the role that social innovation can play in the sustainable development of the Piura region, in Peru, through the implementation of fair trade concepts in banana production. The study focuses on a social investment and social innovation project entitled "Probanano - sustainability of the banana sector as a contribution to poverty reduction in the Piura region." The NGO - OIKOS has started this project in September 2012 and it is expected to be concluded in 2016. It aims to improve life quality and reduce producers, works and comminities poverty in Piura region through sustainable development of the banana sector. This project will benefit 19,000 small farmers, 24,400 workers, 36,600 people indirectly linked to the banana production industry and 26 technicians and employees of municipal and regional authorities. Despite being a project that is not yet completed its analysis already allows us to draw some conclusions such as: Fair Trade practices are social innovations, and after the discussion conducted in the case study, we observed that they return positive results to environmental and social conditions of those who are part of that system. Social innovations do not exclude the need for economic outcomes that are critical to the sustainability of institutions. This case study also aims to investigate whether the project is a case of social innovation as a way to achieve sustainable development of the region

18F-FDG measurement in primary lung cancer: SUV normalization to different distribution volumes

Introduction: Standard Uptake Value (SUV) is a measurement of the uptake in a tumour normalized on the basis of a distribution volume and is used to quantify 18F-Fluorodeoxiglucose (FDG) uptake in tumors, such as primary lung tumor. Several sources of error can affect its accuracy. Normalization can be based on body weight, body surface area (BSA) and lean body mass (LBM). The aim of this study is to compare the influence of 3 normalization volumes in the calculation of SUV: body weight (SUVW), BSA (SUVBSA) and LBM (SUVLBM), with and without glucose correction, in patients with known primary lung tumor. The correlation between SUV and weight, height, blood glucose level, injected activity and time between injection and image acquisition is evaluated. Methods: Sample included 30 subjects (8 female and 22 male) with primary lung tumor, with clinical indication for 18F-FDG Positron Emission Tomography (PET). Images were acquired on a Siemens Biography according to the department’s protocol. Maximum pixel SUVW was obtained for abnormal uptake focus through semiautomatic VOI with Quantification 3D isocontour (threshold 2.5). The concentration of radioactivity (kBq/ml) was obtained from SUVW, SUVBSA, SUVLBM and the glucose corrected SUV were mathematically obtained. Results: Statistically significant differences between SUVW, SUVBSA and SUVLBM and between SUVWgluc, SUVBSAgluc and SUVLBMgluc were observed (p=0.000<0.05). The blood glucose level showed significant positive correlations with SUVW (r=0.371; p=0.043) and SUVLBM (r=0.389; p=0.034). SUVBSA showed independence of variations with the blood glucose level. Conclusion: The measurement of a radiopharmaceutical tumor uptake normalized on the basis of different distribution volumes is still variable. Further investigation on this subject is recommended

Oncological patient anxiety in imaging studies: the PET/CT example

The purpose of this study was to investigate the subjective perception of anxiety pre- and post-procedure, and explore the relationship between demographic, clinical variables and cancer patients' anxiety during a positron emission tomography/computed tomography (PET/CT) scan. Two hundred and thirty-two oncological out patients, with clinical indication for performing an (18)F-2-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/CT scan and attending a nuclear medicine (NM) department, participated in the study. Patients' anxiety and subjective experience of PET/CT were examined using two self-report questionnaires. The pre-procedure questionnaire focused on demographic information, level of knowledge regarding the scan and subjective perception of anxiety before the procedure. The post-procedure questionnaire included the subjective perception anxiety after the procedure, information adequacy and satisfaction with the NM department. The self-reported data indicate that patients were anxious during PET/CT. Furthermore, our data revealed a significant difference between the anxiety pre-procedure and post-procedure (z = -3909, p < 0.05), in which the anxiety pre-procedure has significantly higher values. No significant correlation was found between anxiety and age of the patients, education levels, adequacy of information or satisfaction with the NM Department. Perception of anxiety post-procedure differs between gender (U = 5641, p = 0.033). In conclusion, PET/CT generated anxiety levels in oncological patients, especially before the procedure. Although patients seemed to be satisfied with information delivered by staff and with the NM Department, attention has to be focused on effective interventions strategies that help patients to reduce anxiety

Impact of the background region of interest in the relative renal function

Renal scintigraphy with 99mTc-dimercaptosuccinic acid (99mTc-DMSA) is performed with the aim of detect cortical abnormalities related to urinary tract infection and accurately quantify relative renal function (RRF). For this quantitative assessment Nuclear Medicine Technologist should draw regions of interest (ROI) around each kidney (KROI) and peri-renal background (BKG) ROI, although, controversy still exists about BKG-ROI. The aim of this work was to evaluate the effect of the normalization procedure, number and location of BKG-ROI on the RRF in 99mTc-DMSA scintigraphy

Psychological impact of diagnostic exams

Introduction: Anxiety is a common problem in primary care and specialty medical settings. Treating an anxious patient takes more time and adds stress to staff. Unrecognized anxiety may lead to exam repetition, and impedance of exam performance. Objective: The aim of the study was to examine the anxiety levels of patients who are to undergo diagnostic exams related to cancer diagnostic: PET/CT and mammography. Methods: Two hundred and thirty two patients who undergo PET/CT and one hundred thirteen women who undergo mammography filled out one questionnaire after the procedure to determine their concerns, expectations and perceptions of anxiety. Results: Our results show that the main causes of anxiety in patients who are having a PET/CT is the fear of the procedure itself and fear of the results. Patients who suffered from greater anxiety were those who were scanned during the initial stage of an oncological disease. On the other hand, the diagnostic is the main cause of anxiety in women who are requiring a mammography. 28% of the women reported having experienced pain or intense pain. Conclusions: The performance of diagnostic exams related to cancer diagnostic like a PET/CT and a mammography are important and statistically generators of anxiety. Patients are often poorly informed and present with a range of anxieties that may ultimately affect examination quality. These results provide expertise that can be used in the development of future training programs to integrate post-graduate courses of health professionals

Desenvolvimento de radiofármaco para estudo não invasivo do trânsito intestinal

Tese de mestrado, Química Inorgânica Biomédica (Aplicações em Diagnóstico e Terapia), Universidade de Lisboa, Faculdade de Ciências, 2009No âmbito das patologias gastrointestinais, a Medicina Nuclear contribui com técnicas que permitem estudar, de um modo relativamente não invasivo, alterações da motilidade, nomeadamente o trânsito do cólon, com aplicação clínica em casos de obstipação. A ausência de um radiofármaco de referência torna esta técnica pouco implementada na prática clínica e dificulta a comparação dos resultados de diferentes centros, sendo os valores de sensibilidade e especificidade existentes limitados. A goma de alfarroba (LBG-locust bean gum) e o quitosano são polissacáridos que têm demonstrado ao longo dos anos potencial para diversas aplicações clínicas em imagem médica e, este último, especificamente na Medicina Nuclear. Com o objectivo de desenvolver um radiofármaco de 99mTc, que apresente potencial aplicação clínica nos estudos do trânsito do cólon, foram realizados estudos in vitro para optimização das condições experimentais de síntese e avaliação da estabilidade radioquímica de dois complexos de 99mTc, com goma de alfarroba (LBG-99mTc) e com quitosano (quitosano-99mTc) e estudos em modelo animal (ratinho) para avaliação do comportamento biológico in vivo e determinação da respectiva dosimetria interna. Ao longo da tese sera descritos os procedimentos experimentais realizados e que conduziram a obtenção dos seguintes resultados: após a síntese dos complexos e formulação sob a forma de kit, a avaliação da estabilidade in vitro apresentou resultados de pureza radioquímica superiores a 90% para a LBG-99mTc e para o quitosano-99mTc. Os resultados da biodistribuição e as imagens adquiridas em câmara-gama demonstram a progressão do radiofármaco no tubo digestivo ao longo das 24 horas estudadas, validando a hipótese de que os complexos de 99mTc sintetizado a partir da LBG e do quitosano se mantêm no intestino até serem eliminados por via fecal, não sendo digeridos e/ou absorvidos ao longo do seu percurso. Os órgãos com maior actividade foram o intestino grosso [LBG-99mTc: 33,7% (24h); quitosano-99mTc: 8,2% (12h)] e o intestino delgado [LBG-99mTc: 8,1% (24h); quitosano-99mTc 3,9% (24h)], com excreção renal e hepato-biliar desprezível. A estimativa da dose total efectiva e de 0,037mSv/MBq para a LBG- 99mTc e de 0,095mSv/MBq para o quitosano-99mTc, sendo bastante favorável, em comparação com outros radiofármacos utilizados actualmente na cintigrafia do trânsito do cólon. Os resultados sugerem que a LBG-99mTc e o quitosano-99mTc, quando preparados a partir de soluções congeladas e liofilizadas respectivamente, apresentam características favoráveis para possível aplicação clínica no estudo cintigráfico do trânsito do cólon

Factores que influenciam a estabilidade da 18F-FDG

Introdução – A ausência de um ciclotrão para produção da 2-[18F]Flúor-2-deoxi-D-glucose (18F-FDG) é, actualmente, uma realidade para a maior parte dos centros onde se realizam exames de Tomografia por Emissão de Positrões (TEP), sendo importante garantir a qualidade deste radiofármaco desde o momento da sua síntese até à administração ao doente. O objectivo do estudo é demonstrar a influência dos parâmetros temperatura, pH, concentração radioactiva (CR) e tempo na pureza radioquímica da 18F-FDG. Metodologia – Analisou-se o pH e a pureza radioquímica [por cromatografia em camada fina (CCF)] de seis amostras de 18F-FDG com diferentes CR e em diferentes tempos e temperaturas. Resultados – Registou-se um aumento da percentagem de 18F- aquando do aumento do tempo. Contudo, os resultados não comprovam que a diluição das amostras diminui a degradação do 18F-FDG. No entanto, comparando apenas as amostras diluídas (185 e 740 MBq/ml), observa-se uma relação positiva entre a CR e a percentagem de 18F-. Verificou-se ainda um aumento da percentagem de 18F- nas temperaturas mais elevadas. Conclusão – Sugere-se a diluição das amostras de 18F-FDG e que o tempo de armazenamento não seja muito longo. As amostras devem ainda encontrar-se a temperatura e pH estáveis