This thesis is based on the assumption that the intersection of moral philosophy and practical risk management is a rewarding area to study. In particular, the thesis assumes that concepts, ideas, and methods that are used in moral philosophy can be of great benefit for risk analysis, but also that practices in risk regulation provide a useful testing ground for moral philosophical theories. The thesis consists of an introduction and five articles. Article I is a review article on social and ethical aspects of radiation protection related to nuclear power generation. The paper concludes that four areas of social and ethical issues stand out as central: The first is uncertainty and the influence of value judgments in scientific risk assessments. The second is the distributions of risks and benefits between different individuals, in both space and time. The third is the problem of setting limits when there is no known level of exposure associated with a zero risk. The fourth is related to stakeholder influence and risk communication. Article II discusses ethical issues related to the proposal that doses (or risks) below a certain level should be excluded from the system of radiation protection, without any regard for the number of people exposed. Different arguments for excluding small radiation doses from regulation are examined and a possible solution to the problem of regulating small risks is proposed in the article: Any exclusion of small doses (or risks) from radiation protection ought to be based on a case-by-case basis, with the condition that the expected value of harm remains small. Article III examines what makes one distribution of individual doses better than another distribution. The article introduces a mathematical framework based on preference logic, in which such assessments can be made precisely in terms of comparisons between alternative distributions of individual doses. Principles of radiation protection and from parallel discussions in moral philosophy and welfare economics are defined using this framework and their formal properties analyzed. Article IV argues that the ethical theory of “responsibility-catering prioritarianism” is well positioned to deal with the reasonable requirements in an ethical theory of risk. The article shows how responsibility-catering prioritarianism can be operationalized using a prioritarian social welfare function based on hypothetical utilities. For this purpose, a hypothetical utility measure called ‘responsibility-adjusted utility’ is proposed, which is based on the utility that would normally be expected given circumstances outside of the control of the individual. Article V was written as a response to the Fukushima disaster. Several authors have called the Fukushima disaster a ‘black swan.’ However, the article argues that the hazards of large earthquakes and tsunamis were known before the accident, and introduces and defines the concept of a ‘black elephant,’ as (i) a high-impact event that (ii) lies beyond the realm of regular expectations, but (iii) is ignored despite existing evidence. / QC 20120816

Der Bericht informiert über die Ergebnisse der Auswertung von aerogammaspektrometrischen Befliegungen der Gebiete des ehemaligen Uranerzbergbaus im Freistaat Sachsen in den Jahren 1982 bis 2010. Die Ergebnisse der Datenauswertung zeigen eine übersichtsmäßige Darstellung des Sanierungsfortschrittes an den ehemaligen Uranbergbaustandorten Aue, Johanngeorgenstadt und Zwickau bis zum Jahr 2010 anhand von interpolierten Kartendarstellungen für die Parameter Uran, Thorium und Gamma-Ortsdosisleistung (ODL). Die Veröffentlichung richtet sich sowohl an das Fachpublikum als auch an naturwissenschaftlich interessierte Laien.

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).

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This issue represents contribution to discussion of the population protection within the emergency planning zone of Temelín Nuclear Power Plant (NNP). My intention was to evaluate the actual system of public protection measures in the case of potential appearance of the radiation accident. As a part of this evaluation the analysis of correlation between emergency classification system of emergency events severity, valid for Temelín NPP, and system of immediate protective measures for population was done. The introductory parts of my work describes the basic information about Temelín Nuclear Power Plan. The main attention was given to nuclear safety, radiation protection, principles of emergency preparedness and types of NPP operating modes. Further system of public protection measures for the case of radiation accident appearance is described. Emergency classification system of potential extraordinary events at Temelín NPP and principles of announcements and public warning is also explained in this part. Part of this information represents description of potential implementation of immediate protective actions. One of the outputs is in the form of simple educational software program useful especially for children education. They can received information how to behave in the case of radiation accident declaration. Software is enclosed in the form of compact disk and gain knowledge can be verified by a short test.

Intervention radiology is a discipline that is achieving a great advancement due to its significant success in the treatment of various diseases. Also, it relates to the increase of the number of angiographic performances in the last years. The extension of radiological methods has increased the share of this discipline on the overall medical irradiation of the population. All angiographic performances are accompanied by certain risk related to the exposure of the patient and staff to the ionizing radiation. Several cases were reported where the surface doses were reaching the limits of deterministic effects of radiation in some types of examination. This study monitors three core criteria related to the radiation burden in the set of 141 patients, which have undertaken different endovascular interventions. These criteria are: the dose area product (DAP), surface dose, and effective dosage. The relevant criterion was the value of DAP, read from the DAP meter directly during the examination. Other data were calculated. On basis of these results, this study tries to determine the strenuousness of singular examinations from the point of the radiation burden. It is the understanding the principles of the influencing the patient{\crq}s burden of the radiation in angiographic examinations, what can help in reducing the dosages. The analysis of this study results can help to prevent the occurrence of abnormal events during the examination.

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Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Diagnostic Radiography, Department of Nursing and Radiography in the Faculty of Health Wellness Sciences at Cape Peninsula University of Technology 2014 / Aim: The aim of this study was to record the values of CTDIw and DLP displayed on the Computed Tomography (CT) scanner monitors of patients undergoing CT examinations of the head as Diagnostic Reference Levels (DRL) for dose optimisation in Northern Nigeria. Background: A brain CT scan is the most common CT examination performed, and this modality is recognized as delivering a high dose. CT, therefore, contributes significantly to the total collective effective dose to the population. Elimination of unnecessary or unproductive radiation exposure is necessary. To achieve this, practitioners must adhere to the principles of the justification of practices, and optimisation of radiation protection. Furthermore, the development of DRLs for the local context is advised. These reference doses are a guide to the expected exposure dose from a procedure and are useful as an investigation tool to identify incidences where patient doses are unusually high. Methodology: The study was conducted in three radiology departments with CT centres in Northern Nigeria. Data was collected, using a purposive sampling technique, from 60 consenting adult participants (weighing 70 ±3 kg) that had brain CT scans on seventh generations 4&16-slice GE and 16-slice Philips CT scanners. Prior to commencement of the study the CT scanners were certified by the medical physicists. For each brain scan, patient information, exposure factors, weighted computed tomography dose index (CTDIw), volume computed tomography dose index (CTDIvol) and dose length product (DLP) values were recorded. The data were analysed using SPSS version (16) statistical software. The mean, standard deviation and third quartile values of the CTDIw and DLP were calculated. An inter-comparison of the measured doses from the three research sites was conducted. A combined dose for the three centres was calculated, and compared with the reported data from the international communities where there are established DRLs. Results: The mean CTDIw and DLP values were: centre A (88 mGy and 713 mGy.cm), centre B (68 mGy and 1098 mGy.cm), and centre C (70 mGy and 59 mGy.cm). Comparison of CTDIw and DLP for the scanners of the same manufacturers showed statistically significant differences (p=0.003) and (p=0.03) respectively. In the case of the scanners of a different model but the same number of slices, the comparison of DLP was statistically significant (p=0.005) while no significant difference was noted in the measured CTDIw. Third quartile values of the cumulative doses of CTDIw and DLP, for Northern Nigeria were determined as 77 mGy and 985 mGy.cm respectively. Conclusion: The study has established Local DRLs (LDRLs) which are significantly higher than most of the reported data in the literature. Also dose variation between centres was noted. Optimization is thus recommended. Keywords: Head Imaging, Radiation Dose, Dose optimization, Computed Tomography, Local Diagnostic Reference Levels, Radiation Protection

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Establish limits to the exposure of the population to various ionizing radiation sources is crucial to prevent occupationally exposed individuals and the public, to their deleterious effects. In computational ambit, it is necessary that different exposure scenarios are simulated in order to obtain the dose coefficients (CCs), which relate physical dosimetric quantities - as absorbed dose, Fluency or Kerma Air - with limiting quantities - as equivalent and / or effective dose. Under certain exposure conditions, the individual's posture is not always the same, and the scenario shall be described as realistic as possible. In this work, the AM (Adult Male) and AF (Adult Female) anthropomorphic reference phantom of ICRP publication n° 110 had their postures modified from supine posture (standing) to sitting posture. The change of posture was performed through of a subroutine written in the Visual Monte Carlo code (VMC) to rotate the thigh region of the phantom and position it between the region of the leg and torso. The ScionImage software was used to reconstruct and smooth the knee and hip contours in a sitting posture phantom, and for 3D visualization of phantom was used VolView software. After this step the MCNPX radiation transport code was used for the calculation of fluence-to-dose conversion coefficients (CCs) to six irradiation geometries: AP, PA, LLAT, RLAT, ROT and ISO, recommended by ICRP. The results were compared between the phantoms in standing and sitting postures, for both sexes, in order to assess differences in scattering and absorption of radiation in different postures. The results show significant differences of up to 100% in the equivalent dose conversion coefficients of organs in the pelvic region, 79 % in organs with distribution in the whole body (such as skin, muscle, lymph nodes, bone marrow and trabecular bone) and a difference of 27% to effective dose conversion coefficients. Moreover in order to conduct a comparative study between two types of simulators, was estimated CCs equivalent and effective dose of adult male hybrid simulators, UFHADM, and female, UFHADF, in a sitting posture, and compared to the AM and AF simulators, also in the sitting posture, where it was observed significant difference in energies below 0.05 MeV. This study demonstrated the feasibility of using anthropomorphic phantoms in the sitting posture to represent more realistic postures and can be used in studies in medical and occupational dosimetry. This study demonstrated the feasibility of using anthropomorphic simulators reference in the seated position to represent more realistic positions can thus be used in studies in medical and occupational dosimetry as well as the importance of developing as realistic simulators as possible to dose estimation as faithful as possible in different irradiation scenarios. / Estabelecer limites à exposição da população a diversas fontes de radiação ionizante é de fundamental importância para prevenir indivíduos, ocupacionalmente expostos e do público, dos seus efeitos deletérios. Em âmbito computacional, é necessário que diferentes cenários de exposição sejam simulados, visando à obtenção dos coeficientes de dose (CCs), que associam grandezas dosimétricas físicas – como dose absorvida, fluência ou kerma no ar – com grandezas limitantes – como equivalente e/ou dose efetiva. Em certas condições de exposição a posição do indivíduo nem sempre é a mesma, e o cenário deve ser descrito da forma mais realística possível. Neste trabalho, os simuladores antropomórficos de referência da publicação nº 110 da ICRP, AM (Adult Male) e AF (Adult Female), tiveram suas posturas modificadas da postura supinada (em pé) para a postura sentada. A mudança de postura foi realizada por meio de uma subrotina escrita no software Visual Monte Carlo (VMC) para rotacionar a região da coxa dos simuladores e posicioná-la entre a região da perna e do tronco. O software ScionImage foi utilizado para reconstruir e suavizar os contornos no joelho e quadril dos simuladores na postura sentada, e com ferramenta auxiliar para visualização 3D dos simuladores foi utilizado o software VolView. Após essa etapa foi utilizado o código de transporte de radiação MCNPX para o cálculo dos coeficientes de conversão (CCs) de dose equivalente e efetiva por fluência de partículas, calculados para seis geometrias de irradiação AP, PA, LLAT, RLAT, ROT e ISO, recomendadas pela ICRP. Os resultados foram comparados entre os simuladores em pé e sentado, para ambos os gêneros, com o objetivo de avaliar as diferenças de espalhamento e absorção da radiação para as diferentes posturas. Os resultados dos CCs mostram diferenças significativas, de até 100 % para dose equivalente dos órgãos situados a região pélvica e 79 % em órgãos com distribuição em todo o corpo como, por exemplo, pele, músculo, nódulos linfáticos medula óssea e trabécula óssea, e uma diferença de 14 % para dose efetiva. Ademais, a fim de realizar um estudo comparativo entre dois tipos de simuladores, foi estimado os CCs de dose equivalente e efetiva dos simuladores híbridos adulto masculino, UFHADM, e feminino, UFHADF, na postura sentada, e comparado com os simuladores AM e AF, também na postura sentada, onde foi observado diferença significativa em energias abaixo de 0,05 MeV. Este estudo demonstrou a viabilidade do uso dos simuladores antropomórficos de referência na postura sentada para representar posturas mais realísticas podendo assim, ser utilizado em estudos na dosimetria médica e ocupacional, bem como a importância de desenvolver simuladores tão realista quanto possíveis para estimativa de dose tão fiéis quanto possíveis em diversos cenários de irradiação.

Made available in DSpace on 2014-10-09T12:52:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:56Z (GMT). No. of bitstreams: 0 / O fertilizante é considerado um componente essencial para a agricultura, pois sua utilização aumenta e repõe os nutrientes naturais do solo, perdidos por desgaste ou erosão. No processo de obtenção dos fertilizantes fosfatados, o concentrado de rocha reage com ácido sulfúrico concentrado produzindo ácido fosfórico e sulfato de cálcio (fosfogesso), como subproduto. O ácido fosfórico é utilizado para a produção do superfosfato triplo (TSP), superfosfato simples (SSP), monoamônio fosfato (MAP) e diamônio fosfato (DAP). A rocha fosfatada usada como matéria prima apresenta em sua composição radionuclídeos das séries naturais do urânio e tório. Durante o ataque químico do concentrado de rocha, as espécies presentes na reação, estáveis e radioativas, são redistribuídas entre o ácido fosfórico (matéria prima dos fertilizantes), e o fosfogesso, de acordo com sua solubilidade e características químicas. Enquanto os fertilizantes são comercializados, o fosfogesso fica estocado em pilhas podendo impactar o meio ambiente. Com a finalidade de entender a distribuição dos elementos e dos radionuclídeos no processo industrial de produção de fertilizantes fosfatados, foram analisadas amostras de concentrado de rocha, de fertilizantes (SSP, TSP, MAP e DAP) e fosfogesso de três procedências nacionais denominadas indústrias A, B e C. A técnica utilizada para a análise elementar foi a análise por ativação com nêutrons, que permitiu analisar os elementos Ba, Co, Cr, Fe, Hf, Na, Sc, Ta, Th, U, Zn e Zr, e as terras raras, La, Ce, Nd, Sm, Eu, Tb, Yb e Lu. Os resultados obtidos permitiram concluir que em geral, as terras raras se distribuem de forma homogênea em todos os fertilizantes e no fosfogesso, exceto o Lu. Os fertilizantes SSP e TSP apresentaram concentrações de todos os elementos analisados da mesma ordem de grandeza da rocha de origem. O mesmo comportamento foi observado nos fertilizantes MAP e DAP, exceto para os elementos Co, Sc e U. Os elementos pertencentes à série radioativa natural do urânio (238U, 234U, 230Th, 226Ra e 210Pb), do tório (232Th, 228Ra e 228Th) e o K-40, foram determinados por meio da espectrometria gama e alfa. As amostras de fertilizantes MAP e DAP, que são diretamente derivadas do ácido fosfórico, apresentaram baixa concentração para o 226Ra, 228Ra e 210Pb, enquanto que para o U e Th as concentrações encontradas foram da mesma ordem de grandeza da rocha de origem. Os fertilizantes SSP e TSP, que são obtidos pela mistura de ácido fosfórico com concentrado de rocha, apresentaram concentrações mais elevadas para os radionuclídeos das séries naturais. Avaliou-se a exposição devido a sucessivas aplicações de fertilizantes e fosfogesso, calculando-se a dose interna devida à aplicação por 10, 50 e 100 anos. Os valores encontrados estão abaixo do limite de 2,4 mSv a-1, mostrando que esta prática é negligenciável. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP