Para elaborar um programa de proteção radiológica, as instalações radiativas brasileiras devem considerar normas, diretrizes e recomendações nacionais e internacionais que encontram-se em documentos de diferentes organizações publicados nas últimas décadas: Comissão Internacional de Proteção Radiológica (CIPR), Organismo Internacional de Energia Atômica (OIEA) e Comissão Nacional de Energia Nuclear (CNEN). Visando a proporcionar a essas instalações o acesso às informações pertinentes de forma rápida, integrada e eficiente, este projeto propõe informatizar e disponibilizar em um só documento os programas de otimização da proteção radiológica unificados, inter-relacionados e em português, fornecendo ao público usuário um veículo completo para fins de pesquisa, consulta e informação. A partir do discernimento do que deve conter cada programa e seu real dimensionamento, foi trabalhado o inter-relacionamento das informações de maneira a satisfazer as normas e recomendações nacionais e internacionais. O projeto inclui conceitos, definições e teoria necessários, além da pesquisa detalhada do conteúdo do programa de otimização, das técnicas de ajuda para tomada de decisão, das doses de radiação e detrimento e das informações relacionadas aos custos de proteção. O conteúdo permite responder a todas as questões que devem ser colocadas na elaboração de um programa de otimização de forma a possibilitar montagem do plano de Proteção Radiológica conforme a situação específica do usuário. Para a informatização dos programas de otimização foram estudadas as possibilidades de acesso à Tecnologia da Informação e Comunicação nas empresas brasileiras, possibilitando identificar o perfil de utilização do sistema e definir a estrutura funcional adequada para a criação das melhores interfaces de ferramentas e recursos, bem como de um projeto de navegabilidade eficaz facilitando a busca de informações. O poder de processamento dos servidores aliado à tecnologia dos bancos de dados relacionais permite correlacionar informações advindas de diferentes fontes, possibilitando consultas complexas com tempo de resposta reduzido. O sistema segue o padrão WEB 2.0, que possibilita a estrutura organizacional necessária para a adequada informatização da proteção radiológica e considera os corretos critérios de indexação da informação para garantir seu reconhecimento pelos motores de busca da internet. O projeto conta com a combinação de várias tecnologias, potencializando os recursos disponíveis em cada uma delas para alcançar os objetivos propostos. Este trabalho experimental lança um cerne inicial para a informatização dos programas de proteção radiológica, informatizando inicialmente os programas de otimização. A investigação do perfil de utilização durante um período de cinco meses possibilitou o levantamento de dados importantes que apontam novas possibilidades para o desenvolvimento da informatização dos programas de proteção radiológica. Pretende-se, a partir dos resultados deste projeto, aprofundar o trabalho de investigação e completar a execução do sistema de informatização. / In order to establish a Radiation Protection Plan or a Radiation Emergency Plan, Brazilian facilities should take into account all procedures based on both national and international standards, guidelines and recommendations. This information can be found in several documents published by different organizations over the past decades, namely: the International Commission on Radiological Protection (ICRP), International Atomic Energy Agency (IAEA) and Comissão Nacional de Energia Nuclear (CNEN). This project aims the informatization of the radiological protection optimization programs in a single system in order to offer unified programs and inter-related information in Portuguese, providing Brazilian radioactive facilities a complete repository for research, consultation and information. In order to meet both national and international recommendations within the scope of this work, we conducted a comprehensive job of perception about each program contents as well as its real dimension, identifying and detailing the vital parts of programs. The content includes concepts, definitions and theory in addition to the optimization programs, help decision making techniques, information related to protection costs, radiation doses and detriment. The content allows to answer to every question when an optimization program is elaborated, according to decision maker´s specific situation. For dimensioning the work of informatization and developing the WEB platform according to the needs of the target public profile, we have conducted an extensive research regarding the possibilities of Information and Communication Technology access in companies throughout the country. That allowed us to define the best interfaces tools and resources. The servers processing power added to the technology of relational databases allow to integrate information from different sources, enabling complex queries with reduced response time. The project was implemented in a web environment, using the Web 2.0 tools and resources that allow the entire organizational structure, that would enable the inter-relationships and joints needed for proper use of information technology in radiological protection. The correct indexing of contents guarantees that search engines will find the desired information in the shortest time possible. This project uses the combination of multiple technologies, maximizing the resources available in each one of them in order to achieve our goals. For now we intend to begin an initial core working only the optimization program, which in the near future could be extended to other fields of radiological protection. The investigation of the usage profile for five months enabled important data that suggest new possibilities for the development of computerization of radiation protection programs. According to the results of this project, we intend to lead a further research work and complete the informatization system.

Nos travaux portent sur la réduction de la dose de rayonnement lors d'examens réalisés avec le Système de radiologie EOS. Deux approches complémentaires sont étudiées. Dans un premier temps, nous proposons une méthode de débruitage et de rehaussement de contraste conjoints pour optimiser le compromis entre la qualité des images et la dose de rayons X. Nous étendons le filtre à moyennes non locales pour restaurer les images EOS. Nous étudions ensuite comment combiner ce filtre à une méthode de rehaussement de contraste multi-échelles. La qualité des images cliniques est optimisée grâce à des fonctions limitant l'augmentation du bruit selon la quantité d’information locale redondante captée par le filtre. Dans un deuxième temps, nous estimons des indices d’exposition (EI) sur les images EOS afin de donner aux utilisateurs un retour immédiat sur la qualité de l'image acquise. Nous proposons ainsi une méthode reposant sur la détection de points de repère qui, grâce à l'exploitation de la redondance de mesures locales, est plus robuste à la présence de données aberrantes que les méthodes existantes. En conclusion, la méthode de débruitage et de rehaussement de contraste conjoints donne des meilleurs résultats que ceux obtenus par un algorithme exploité en routine clinique. La qualité des images EOS peut être quantifiée de manière robuste par des indices calculés automatiquement. Étant donnée la cohérence des mesures sur des images de pré-affichage, ces indices pourraient être utilisés en entrée d'un système de gestion automatique des expositions. / We aim at reducing the ALARA (As Low As Reasonably Achievable) dose limits for images acquired with EOS full-body system by means of image processing techniques. Two complementary approaches are studied. First, we define a post-processing method that optimizes the trade-off between acquired image quality and X-ray dose. The Non-Local means filter is extended to restore EOS images. We then study how to combine it with a multi-scale contrast enhancement technique. The image quality for the diagnosis is optimized by defining non-parametric noise containment maps that limit the increase of noise depending on the amount of local redundant information captured by the filter. Secondly, we estimate exposure index (EI) values on EOS images which give an immediate feedback on image quality to help radiographers to verify the correct exposure level of the X-ray examination. We propose a landmark detection based approach that is more robust to potential outliers than existing methods as it exploits the redundancy of local estimates. Finally, the proposed joint denoising and contrast enhancement technique significantly increases the image quality with respect to an algorithm used in clinical routine. Robust image quality indicators can be automatically associated with clinical EOS images. Given the consistency of the measures assessed on preview images, these indices could be used to drive an exposure management system in charge of defining the optimal radiation exposure.

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Made available in DSpace on 2014-10-09T12:47:07Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:37Z (GMT). No. of bitstreams: 1 07969.pdf: 4735290 bytes, checksum: 35766584f698fd08a530a144cb0a0bd0 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

No description available.

Introduction: Despite the relatively low dose (0.5 mSv – 1 mSv) generated by Attenuation Correction CT (ACCT) in PET examinations, the ALARA principle is still applicable. The currently used ACCT standard protocol at the Karolinska University Hospital in Solna uses 7.6 effective mAs (mAseff) and 120 kVp, but reducing mAseff and/or kVp would decrease patient dose as well as facilitate an increased number of research subjects. A CT reconstruction algorithm called Quantification Achieved Consistently (Q.AC.) (Lonn, 2012) has recently been developed to enable reduced doses from ACCT, while preserving quantitative PET data. The purposes of this study were to investigate possible limitations of the Q.AC. with respect to patient size, and to optimise protocols, aiming at minimising ACCT dose in terms of Volumetric Computer Tomography Dose Index CTDIvol. Methods: Measurements were performed with a GE PET/CT Discovery system, which offers Q.AC. reconstruction. The NEMA NU-2 protocol was followed to quantify PET quality, including evaluations of relative count error in the artificial lung in the phantom centre (lung), hot- and cold-sphere contrast (Q), and background variability (N). Two phantoms were used; the NEMA body phantom (elliptical cross section sized 30 cm laterally and 23 cm anterior-posterior (AP)), here representing paediatric patients and small-sized adults, and the same phantom with an additional (20 cm laterally and 4 cm AP) ellipsoid plastic (PMMA) extension ring, representing mid- and large-sized patients. ACCTs were acquired with 15 mAseff values, range [2.3 - 260], in combination with four kVp values [80, 100, 120, 140] and reconstructed with two algorithms (Q.AC. and a regular soft CT algorithm). Consequently, PET reconstructions were performed based on each mAseff, kVp and CT-reconstruction combination. Results: Quantitatively similar PET results to the standard protocol were achieved with the Q.AC. CT reconstruction algorithm using a CTDIvol = 0.06 mGy (2.3 mAseff and 80 kVp) for the NEMA body phantom, respectively a CTDIvol = 0.20 mGy (2.3 mAseff and 120 kVp) for the phantom with additional extension ring. Conclusions: This study indicates that the Q.AC. CT reconstruction algorithm enables accurate PET results at lower ACCT mAseff and kVp settings than the currently used clinical standard protocol. For paediatric patients and small-sized adults, a reduction of CTDIvol by approximately 90% may be achieved, while for mid- and large-sized patients, the CTDIvol can be reduced by approximately 70% without loss of quantitative PET data.

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Thesis (M.Med. (Diagnostic Radiology)) -- University of Limpopo, 2022 / BACKGROUND: Ionizing radiation is detrimental to growing cells. The potential risk of any dose of radiation in growing cells can lead to permanent damage of basic cellular structure resulting in a high risk of developing cancer in children. Therefore, paediatric doctors need sufficient knowledge to protect their patients from late effects of radiation resulting from medical use. Most studies report poor knowledge of radiation safety measures among doctors. PURPOSE: The purpose of this study is to assess the knowledge of radiation safety and radiation doses among paediatric doctors in Pietersburg and Mankweng Hospitals, Limpopo province, South Africa. OBJECTIVE: To assess the paediatric doctors’ knowledge of radiation doses used in radiological diagnostic imaging examinations, as well as their knowledge of radiation safety measures. METHODOLOGY: This is a survey of paediatric doctors in the paediatrics general ward, paediatric oncology, intensive care and neonatal units, and paediatric surgery department, at Pietersburg and Mankweng Hospitals. A self-administered questionnaire with 23 items on knowledge of radiation safety and radiation doses emitted during normal radiological examinations is used to collect the data in May 2021. Data are analysed using Statistical Package for Social Sciences (SSPS) version 26.0 software. Chi-squared test is used to analyse the relationship between variables. Analysis of variance (ANOVA) is used to analyse the differences between variables. A p value of <0.05 is considered statistically significant. A total score of 50% in each section is used to denote adequate knowledge. The result are presented in charts and tables. RESULTS: Out of 52 paediatric doctors, 47 completed the questionnaire achieving a 90.4% response rate. Majority of participants were females (n = 31; 66%). Overall, only 10 (21.2%) of the participants scored 50% and above, including three consultants, two registrars, two medical officers and one medical officer intern. Twenty-five (53.1%) participants scored 50% and above on knowledge of radiation safety. Nearly half (44.7%) of the doctors were familiar with the concept of ALARA principle in radiation dose optimisation. Three participants scored more than 50% in the knowledge of radiation doses section. Only five (10.6%) and 17 (36%) participants correctly identified MRI and ultrasound, respectively, as the radiological diagnostic modalities that do not utilize ionizing radiation. CONCUSION: The level of knowledge of radiation safety and radiation doses among the paediatric doctors are poor. A very small number of the paediatric doctors were able to identify non-ionizing radiation modalities that can be used as an alternative to reduce radiation exposure to paediatrics during radiological investigations. Paediatric doctors will benefit from courses on radiation safety and radiation doses to improve their knowledge and/or eliminate unwarranted exposure of their patients to ionizing radiation.

Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-21T11:45:58Z No. of bitstreams: 0 / Made available in DSpace on 2017-11-21T11:45:58Z (GMT). No. of bitstreams: 0 / O gerenciamento de riscos em uma instalação nuclear é necessário para a segurança de trabalhadores e de populações vizinhas. Parte desse processo é a comunicação dos riscos que propicia o diálogo entre gestores da empresa e moradores das áreas de risco. A população que conhece os riscos a que está exposta, como esses riscos são gerenciados e o que deve ser feito em uma situação de emergência tende a se sentir mais segura e a confiar nas instituições responsáveis pelo plano de emergência. Sem diálogo entre empresa e público, o conhecimento dos procedimentos a serem seguidos em caso de acidente não chega à população, ou quando chega, não há confiança dessas pessoas na sua eficácia. Em Angra dos Reis, no litoral sul do Estado do Rio de Janeiro, está a Central Nuclear Almirante Álvaro Alberto. No entorno dessa Central Nuclear existe uma população que, de acordo com o Plano de Emergência Externo (PEE/RJ), deverá ser evacuada ou ficar abrigada, caso ocorra um acidente na instalação. Um trabalho de comunicação de riscos entre esses moradores é necessário para que eles conheçam o plano de emergência e os procedimentos corretos para uma situação de emergência, além de buscar esclarecer dúvidas e mitos. Esse trabalho apresenta uma análise da comunicação dos riscos feita para a população local, a percepção que ela tem dos riscos e o grau de conhecimento do plano de emergência externo por parte dessas pessoas. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP