ESTeSL - Escola Superior de Tecnologia da Saúde de Lisboa
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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.
- 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, L.; Ahmed, A.; Harderwijk, M.; Nasir, S.; Ndlovu, J.; Oliveira, M.; Santiago, A.; Hogg, PeterPurpose: This study aims to investigate the influence of tube potential (kVp) variation in relation to perceptual image quality and effective dose 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 2 AFC visual grading software. PCXMC software was used to estimate the effective dose. 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. Effective dose results show a statistical significant decrease (p=0.000) on the 75th quartile from 0.3 mSv at 60 kVp to 0.1 mSv at 120 kVp when applying the 10 kVp rule in non-AEC mode. Conclusion: No significant reduction in perceptual image quality is observed when increasing kVp whilst a marked and significant effective dose reduction is observed.
- 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, L.; Ahmed, A.; Harderwijk, M.; Marti, C.; Nasir, S.; Ndlovu, J.; Oliveira, M.; Santiago, A.; Hogg, PeterBackground - Pelvis and hip radiography are consistently found to be amongst the highest contributors to the collective effective dose (E) in all ten DOSE DATAMED countries in Europe, representing 2.8 to 9.4% of total collective dose (S) in the TOP 20 exams list. The level of image quality should provide all the diagnostic information in order not to jeopardise the diagnosis, but being able to provide the needed clinical information with the minimum dose. A recent study suggests further research to determine whether the “10 kVp rule” would have value for a range of examinations using Computed Radiography (CR) systems. As a “rule of thumb” increasing the kVp by 10 whilst halving the mAs is suggested to give a similar perceptual image quality when compared to the original exposure factors. Aims - In light of the 10kVp rule, this study aims to investigate the influence of tube potential (kVp) variation in relation to perceptual image quality and E for pelvis imaging using automatic exposure control (AEC) and non-AEC in a Computed Radiography (CR) system. Research questions - Does the 10kVp rule works for the pelvis in relation to image quality in a CR system? Does the image quality differs when the AEC is used instead of manual mode using the 10kVp rule and how this impacts on E?
- 131I therapy in thyroid cancer and benign thyroid diseases: personal dose equivalent HP(10) assessment in patient’s close family membersPublication . Raminhas Carapinha, Maria João; Costa, Gracinda; Ferreira, Teresa C.; Salgado, Lucília; Vaz, Sofia; Ferreira, Rui; Isidoro, Jorge; Rézio, Teresa; Nunes, Carla; Tavares, António Barata; Vaz, PedroIntroduction - The aim is to quantify the personal dose equivalent HP(10) in the family members (FMs) of the patients (PATs) undergoing iodine-131 thyroid cancer (TC) therapy and benign thyroid diseases (BTD) and to compare the HP(10) values of children and adults. Methods - An observational study with convenience sampling was performed, including 83 FMs (59% ♂) of 48 PATs (72.9% ♀). All FMs wore a whole body TLD for 21 days and received instructions on radiation protection, based on Euratom recommendations. All FMs were provided with relevant instructions for TLD use and answered a questionnaire. Two groups were defined: Group-TC, included 65 FMs (5 children below the age of 10) of 37 PATs treated for TC with average (ᾱ) activity of 3434MBq (range 1110–5920MBq); Group-BTD included 18 FMs adults of 11 PATs treated for BTD with ᾱ activity of 336.4MBq (range 185–555MBq). The in-PATs of Group-TC were discharged 48h after therapy. All ethical principles of the investigation were respected. Results - When the PATs of Group-TC were discharged the ᾱ effective dose rate measured at a 1-metre distance was 10.4μSv/h (range 2–28μSv/h). The ᾱ value of HP(10) in FMs were: 0.14mSv (range 0.00-3.37mSv) for Group-TC and 0.37mSv (range 0.01-2.40mSv) for Group-BTD. The HP(10) value depended on the degree of relationship (p=0.008) and the age of the FMs (p=0.007). HP(10) of the FMs were moderately associated to administered activity (ρsp=-0.319; p=0.010) in Group-TC. No association was found between HP(10) FMs and the administered activity in Group-BTD (ρsp=0.139; p=0.583). Conclusions - The FMs of the PATs submitted 131I therapy for BTD received higher doses when compared to FMs of TC PATs. The HP(10) of the FMs depended to the degree of relationship and the age of the FMs. In the PATs submitted 131I therapy for BTD, the HP(10) of the FMs is not associated with the administered activity. The personal dose equivalent in these FMs does not reach the dose limits recommended by ICRP 97 and ICRP 94.
- 18F-FDG measurement in primary lung cancer: SUV normalization to different distribution volumesPublication . Badgi, Estevão; Santos, Beatriz; Lucena, Filipa; Conde, IsabelIntroduction: 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.
- 18FDG PET/CT in the qualitative and quantitative evaluation of the therapeutic response in Hodgkin’s lymphomaPublication . Martins, Nuno; Hunter, James; Vaz, Tânia; Dizdarevic, Sabina
- 25 Anos de diagnóstico em fisiopatologia respiratóriaPublication . Dias, Hermínia Brites
- 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.
- 3D-2D image registration by nonlinear regressionPublication . Gouveia, A. R.; Metz, C.; Freire, Luís; Klein, S.We propose a 3D-2D image registration method that relates image features of 2D projection images to the transformation parameters of the 3D image by nonlinear regression. The method is compared with a conventional registration method based on iterative optimization. For evaluation, simulated X-ray images (DRRs) were generated from coronary artery tree models derived from 3D CTA scans. Registration of nine vessel trees was performed, and the alignment quality was measured by the mean target registration error (mTRE). The regression approach was shown to be slightly less accurate, but much more robust than the method based on an iterative optimization approach.
- 40 Anos da revista Análise Psicológica (1977-2017): análise bibliométricaPublication . Antunes, Maria Da Luz; Lopes, Carlos; Seguro-de-Carvalho, Paula; Nunes, Paulo; Carvalho-Teixeira, JoséA presente comunicação tem como objetivo analisar os artigos publicados na revista Análise Psicológica e estudar a sua trajetória científica no campo da Psicologia em Portugal. O estudo em análise abrange 40 anos de evolução, desde 1977 a 2017 (considerando que no período de 1983-1986 não foi publicada). A análise assenta na metodologia bibliométrica, com enfoque quantitativo, relacional e diacrónica da produção, autoria, proveniência institucional e temáticas abordadas dos artigos publicados. Foram analisados 1.730 textos entre artigos, editoriais, relatos de experiências, notas didáticas, revisões de livros e outros. O material foi analisado e organizado a partir de um conjunto de categorias: (a) análise da produção; (b) análise da autoria; (c) análise da produtividade dos autores; (d) análise da produtividade institucional; (e) análise da afiliação institucional dos autores; (f) idioma dos textos; (g) tipo de textos; e (h) enfoque metodológico. Por fim, realizou-se uma análise temática com suporte ao vocabulário controlado e às palavras-chave mais frequentes ao longo dos artigos da revista. A partir dos resultados foi possível traçar uma linha do tempo das principais mudanças editoriais da revista Análise Psicológica. O estudo analisa a evolução da revista Análise Psicológica no seu 40º aniversário por uma linha do tempo caracterizada em quatro etapas: 1. Nascimento; 2. Crescimento; 3. Maturidade; e 4. Internacionalização. Este estudo fornece-nos, ainda, dados que podem ajudar a melhor entender o papel da revista Análise Psicológica na promoção da Psicologia em Portugal, bem como o acompanhamento dos mais recentes desenvolvimentos tecnológicos (e.g., DOI, ORCID, OJS). Como perspetivas futuras da revista destacam-se a integração e participação no movimento de Acesso Aberto (via dourada: SciELO, Redalyc, RCAAP, entre outras) e a sua internacionalização através da indexação em bases de dados como a SCOPUS, a Web of Science e a PsycINFO.