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- 10 kVp rule – An anthropomorphic pelvis phantom imaging study using a CR system: impact on image quality and effective dose using AEC and manual modePublication . Lança, Luís; Franco, Loris; Ahmed, Abdulfatah; Harderwijk, Marloes; Narti, Chloe; Nasir, Sadeeda; Ndlovu, Junior; Oliveira, Miguel; Santiago, Ana Rita; Hogg, PeterPurpose - This study aims to investigate the influence of tube potential (kVp) variation in relation to perceptual image quality and effective dose (E) for pelvis using automatic exposure control (AEC) and non-AEC in a Computed Radiography (CR) system. Methods and materials - To determine the effects of using AEC and non-AEC by applying the 10 kVp rule in two experiments using an anthropomorphic pelvis phantom. Images were acquired using 10 kVp increments (60–120 kVp) for both experiments. The first experiment, based on seven AEC combinations, produced 49 images. The mean mAs from each kVp increment were used as a baseline for the second experiment producing 35 images. A total of 84 images were produced and a panel of 5 experienced observers participated for the image scoring using the two alternative forced choice (2AFC) visual grading software. PCXMC software was used to estimate E. Results - A decrease in perceptual image quality as the kVp increases was observed both in non-AEC and AEC experiments, however no significant statistical differences (p > 0.05) were found. Image quality scores from all observers at 10 kVp increments for all mAs values using non-AEC mode demonstrates a better score up to 90 kVp. E results show a statistically significant decrease (p = 0.000) on the 75th quartile from 0.37 mSv at 60 kVp to 0.13 mSv at 120 kVp when applying the 10 kVp rule in non-AEC mode. Conclusion - Using the 10 kVp rule, no significant reduction in perceptual image quality is observed when increasing kVp whilst a marked and significant E reduction is observed.
- 3D printing of abdominal immobilization masks for therapeutics: dosimetric, mechanical and financial analysisPublication . Duarte, Jessica; Loja, Maria Amélia Ramos; Portal, Ricardo; Vieira, Lina OliveiraMolding immobilization masks is a time-consuming process, strongly dependent on the healthcare professional, and potentially uncomfortable for the patient. Thus, an alternative sustainable automated production process is proposed for abdominal masks, using fused deposition modelling (FDM) 3D printing with polylactic acid (PLA). Radiological properties of PLA were evaluated by submitting a set of PLA plates to photon beam radiation, while estimations of their mechanical characteristics were assessed through numerical simulation. Based on the obtained results, the abdominal mask was 3D printed and process costs and times were analyzed. The plates revealed dose transmissions similar to the conventional mask at all energies, and mechanical deformation guarantees the required immobilization, with a 66% final cost reduction. PLA proved to be an excellent material for this purpose. Despite the increase in labour costs, a significant reduction in material costs is observed with the proposed process. However, the time results are not favorable, mainly due to the printing technique used in this study.
- 4DCT versus 4DPET/CT na avaliação do movimento respiratório no planeamento da radioterapia no cancro do pulmão de não pequenas células: revisão da literaturaPublication . Dias, Paulo; Neves, Samuel; Raminhas Carapinha, Maria João; Caetano, MarcoIntrodução – Uma das abordagens terapêuticas no carcinoma do pulmão de não pequenas células (CPNPC) é a quimioterapia e radioterapia (RT) concomitante. O planeamento de RT pode ser realizado com base em diferentes técnicas de imagem, existindo vários fatores que podem influenciar a qualidade das mesmas, nomeadamente o movimento respiratório. Objetivos – Este estudo tem como objetivos: 1) avaliar a importância da 4DCT e da 4DPET/CT para a correção de movimento e definição do volume alvo no planeamento de RT para CPNPC; e 2) comparar a delimitação de volumes entre as técnicas PET/CT, 4DCT e 4DPET/CT, identificando as suas vantagens e limitações. Métodos – Revisão da literatura, recorrendo-se à metodologia PRISMA para a seleção de artigos nas bases de dados PubMed e Science Direct e outras fontes (b-on e Google Scholar). Foram considerados artigos publicados entre janeiro de 2014 e janeiro de 2020. Foram comparados volumes delimitados através de técnicas 3D e 4D, avaliando o impacto do movimento respiratório na aquisição de imagens e posterior planeamento de RT. Resultados – Obtiveram-se 230 artigos, mas apenas cinco foram elegíveis para estudo. As técnicas 4DCT e 4DPET/CT apresentaram melhores resultados, diminuindo os artefactos de movimento. Os volumes delimitados pelas várias técnicas em estudo foram semelhantes, apesar de se registarem pequenas variações quando a técnica 4D não é aplicada. Conclusão – Atualmente a 4DPET/CT apresenta melhores resultados na delimitação de volumes alvo para o planeamento de RT do que a técnica 4DCT.
- 5' and 3' UTR thymidylate synthase polymorphisms modulate the risk of colorectal cancer independently of the intake of methyl group donorsPublication . Carmona, Bruno; Guerreiro, Catarina Sousa; Cravo, Marília; Leitão, Carlos Nobre; Brito, MiguelThymidylate synthase, as a rate-limiting step in DNA synthesis, catalyses the conversion of dUMP into dTMP using 5,10-methylenotetrahydrofolate as the methyl donor. Two polymorphisms have been described in this gene: a repeat polymorphism in the 5' promoter enhancer region (3R versus 2R) and a 6 bp deletion in the 3' unstranslated region. Both of these may affect protein levels. The present case control study was aimed at investigating the influence of these two polymorphisms on the development of colorectal cancer (CRC), as well as their potential interaction with folate, vitamin B6 and vitamin B12 intake. A total of 196 cases and 200 controls, matched for age and sex distribution, were included in the study. No association was found between CRC and the 28 bp repeat polymorphism, but it was observed that individuals with the 6 bp/del and del/del genotypes had a significantly lower risk of developing the disease (OR=0.47; 95% CI 0.30-0.72). A combined genotype (2R/2R; 6 bp/del+del/del) was also found, which was associated with an even lower risk of developing of the disease (OR=0.42; 95% CI 0.26-0.69). No significant interaction between these polymorphisms and vitamin intake was observed. These results indicate for the first time that the 6 bp/del allele might be a protective factor in the development of CRC, independent of the intake of methyl group donors.
- A 5-year follow-up of the benefits of an exercise training program in liver recipients transplanted due to familial amyloidotic polyneuropathyPublication . Tomás, Maria Teresa; Melo, Xavier; Mateus, Élia; Gonçalves, Mafalda; Barroso, Eduardo; Santa-Clara, HelenaBackground: Supervised (SE) and home-based exercise (HBE) training regimes are effective on reconditioning patients with familial amyloidotic polyneuropathy (FAP) after liver transplantation, but research of the long-term retention of the benefits attained in patients with FAP has not yet been conducted. Purpose: In this 5-year follow-up study, we aimed to determine whether the exercise training gains in body composition, physical activity, and function promoted by a 24-week SE or HBE training regimes are retained in patients with FAP who resume normal activity. Methodology: Sixteen liver-transplanted patients with FAP were reassessed for body composition (dual X-ray absorptiometry), physical activity (questionnaire), and function (handgrip strength and 6-minute walk test). Results: Total body fat increased with both exercise regimes during follow-up ( P < .05; η2 = 0.432-0.625) as well as femoral neck bone density ( P = .048; η2 = 0.119). However, gains in upper limbs muscle quality during follow-up ( P < .001; η2 = 0.597) were only found in the SE group ( P = .042; η2 = 0.245). Both exercise regimes showed retaining aptitudes in walking capacity ( P < .05; η2 = 0.329-0.460) and muscle mass ( P = .05; η2 = 0.245). Still, none could retain the physical activity levels. Conclusion: Long-term resumption of normal activity following a 24-week SE or HBE regime in patients with FAP resulted in a loss of exercise-induced increases in physical activity but counterweighted postoperative losses in bone mineral density and substantially retained the benefits in walking capacity, muscle mass, and quality, in particular, in the SE group.
- Abdominal MRI synthesis using styleGAN2-ADAPublication . Gonçalves, Bernardo; Vieira, Pedro; Vieira, AnaThe lack of labeled medical data still poses one of the biggest issues when creating Deep Learning models in the medical field. Modern data augmentation techniques like the generation of synthetic images have gained a special interest. In recent years there has been a significant improvement in GANs. StyleGAN2 achieves impressive results in the generation of natural images. StyleGAN2-ADA was created to respond to the lack of training data when training an image synthesis model, which is very frequent in the medical field. Some works used styleGAN to generate melanomas, breast cancer histological images, and MR and CT images. In this work, we apply, for the first time, a styleGAN2-ADA to a small dataset of abdominal MRI with 1.3k images. From the augmentation pipeline created by the authors of styleGAN2-ADA, we removed all augmentations except the geometric transformations and pixel blitting operations. We trained our network for 70 hours. Our generated dataset has a precision score of 59,33 % and a FID score of 18,14. We conclude that the styleGAN2-ADA is a viable solution to generate MRI using a small dataset.
- A abordagem do técnico de radiologia na triagem ortopédica em urgência hospitalarPublication . Ribeiro, Ricardo; Matos, IsabelIntrodução - O presente trabalho de investigação tem como objectivo identificar o processo adoptado pelos técnicos de radiologia no desempenho das suas tarefas específicas da triagem ortopédica do referido hospital de Lisboa. Metodologia - Os dados foram recolhidos junto de um grupo de técnicos de radiologia da urgência de um Hospital na região de Lisboa, por meio de entrevistas semi-estruturadas realizadas a 11 indivíduos e analisados através da técnica da análise de conteúdo, utilizando como referencial os princípios bioéticos da autonomia dos profissionais. Resultados - No processo de análise, emergiram três categorias no atendimento da triagem ortopédica aos doentes: a realização do exame; a avaliação da triagem realizada pelos técnicos de radiologia; o papel dos técnicos de radiologia na triagem ortopédica. Conclusões - Este estudo permitiu concluir que o técnico de radiologia tem capacidade técnica de decisão na escolha das incidências radiológicas mais adequadas ao estado clínico do paciente, no contexto da triagem radiológica. O estudo revela a necessidade de formação nesta área especifica.
- Abordagem nutricional e dietética na prevenção e tratamento da hipertensão arterialPublication . Mendes, Diana; Silva, Pedro Marques daDe natureza multifatorial, a elevação da pressão arterial resulta da combinação intrincada de fatores genéticos, fisiológicos e ambientais. Diversos estudos epidemiológicos, meta-análises e estudos experimentais confirmam o papel de certos padrões alimentares (DASH e dieta mediterrânica) e de vários nutrientes e fatores dietéticos no desenvolvimento da hipertensão arterial (ou na sua modulação favorável ou desfavorável). As alterações nutricionais podem diminuir a pressão arterial e prevenir o desenvolvimento de hipertensão arterial, com implicações potenciais na morbilidade e mortalidade cardiovascular. Pretende-se sumariar alguns dos fatores dietéticos e nutricionais mais importantes relacionados com a síndrome hipertensiva.
- Absence of Gim proteins, but not GimC complex, alters stress-induced transcriptionPublication . Amorim, Ana Fátima; Pinto, Dora; Kuras, Laurent; Fernandes, LiseteSaccharomyces cerevisiae GimC (mammalian Prefoldin) is a hexameric (Gim1-6) cytoplasmic complex involved in the folding pathway of actin/tubulin. In contrast to a shared role in GimC complex, we show that absence of individual Gim proteins results in distinct stress responses. No concomitant alteration in F-actin integrity was observed. Transcription of stress responsive genes is altered in gim2Δ, gim3Δ and gim6Δ mutants: TRX2 gene is induced in these mutants but with a profile diverging from type cells, whereas CTT1 and HSP26 fail to be induced. Remaining gimΔ mutants display stress transcript abundance comparable to wild type cells. No alteration in the nuclear localization of the transcriptional activators for TRX2 (Yap1) and CTT1/HSP26 (Msn2) was observed in gim2Δ. In accordance with TRX2 induction, RNA polymerase II occupancy at TRX2 discriminates the wild type from gim2Δ and gim6Δ. In contrast, RNA polymerase II occupancy at CTT1 is similar in wild type and gim2Δ, but higher in gim6Δ. The absence of active RNA polymerase II at CTT1 in gim2Δ, but not in wild type and gim1Δ, explains the respective CTT1 transcript outputs. Altogether our results put forward the need of Gim2, Gim3 and Gim6 in oxidative and osmotic stress activated transcription; others Gim proteins are dispensable. Consequently, the participation of Gim proteins in activated-transcription is independent from the GimC complex.
- Absolute hyperglycemia versus stress hyperglycemia ratio for the prognosis of hospitalized patients with COVID-19 in the first months of the pandemic: a retrospective studyPublication . Matias, Alexandra A.; Manique, Inês; Sabino, Teresa; Rego, Teresa; Mihon, Claudia; Panarra, António; Rizzo, Manfredi; Silva-Nunes, JoséDiabetes is a risk factor for the greater severity of coronavirus disease 2019 (COVID-19). The stress hyperglycemia ratio (SHR) is an independent predictor of critical illness, and it is reported to have a stronger association than absolute hyperglycemia. The aim of this study was to assess the relationship between absolute hyperglycemia and SHR with the severity of COVID-19 since there are no studies investigating SHR in patients with COVID-19. We conducted a retrospective observational study on hospitalized patients with COVID-19 in the first months of the pandemic, regarding absolute hyperglycemia, SHR, and severity outcomes. Of the 374 patients, 28.1% had a previous diagnosis of type 2 diabetes. Absolute hyperglycemia (64.8% versus 22.7%; p < 0.01) and SHR [1.1 (IQR 0.9-1.3) versus 1.0 (IQR 0.9-1.2); p < 0.001] showed a statistically significant association with previous diabetes. Absolute hyperglycemia showed a significant association with the clinical severity of COVID-19 (79.0% versus 62.7%; p < 0.001), need for oxygen therapy (74.8% versus 54.4%; p < 0.001), invasive mechanical ventilation (28.6% versus 11.6%; p < 0.001), and intensive care unit (30.3% versus 14.9%; p = 0.002), but not with mortality; by contrast, there was no statistically significant association between SHR and all these parameters. Our results are in agreement with the literature regarding the impact of absolute hyperglycemia on COVID-19 severity outcomes, while SHR was not a significant marker. We, therefore, suggest that SHR should not be evaluated in all patients admitted to the hospital for COVID-19, and we encourage the standard measures at the admission of blood glucose and HbA1c levels.