Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-21T19:51:42Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL versão digital.pdf: 2839254 bytes, checksum: 962b7ff83b975bcd276b612274de7368 (MD5) / Made available in DSpace on 2017-03-21T19:51:42Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL versão digital.pdf: 2839254 bytes, checksum: 962b7ff83b975bcd276b612274de7368 (MD5) Previous issue date: 2016-08-15 / Facepe / Dentre os diversos procedimentos intervencionistas com fins terapêuticos, a quimioembolização hepática tem se destacado por ser de alta complexidade e resultar em altas doses de radiação aos pacientes e à equipe médica. Em alguns casos, o paciente requer várias sessões para tratar a mesma lesão, o que aumenta a probabilidade de ocorrência de lesões na pele e/ou efeitos estocásticos. Embora seja uma técnica altamente utilizada no Brasil, a quimioembolização não tem sido alvo de estudos dosimétricos. Este estudo apresenta os resultados da avaliação dosimétrica realizada na equipe médica e pacientes durante 109 procedimentos de quimioembolização hepática, realizados em seis serviços de hemodinâmica na cidade de Recife, Pernambuco. Os procedimentos foram realizados utilizando equipamentos de angiografia digital de diferentes fabricantes e tecnologias. A dosimetria dos pacientes foi caracterizada através das estimativas da máxima dose na pele (MDP), do produto kerma ar-área (PKA) e do kerma ar de referência (Ka,r). A MDP foi estimada a partir da utilização de filmes radiocrômicos do tipo Gafchromic XR RV3. Para avaliar o risco de efeitos estocásticos, foi estimada a dose absorvida em órgãos a partir de simulações Monte Carlo utilizando fantomas antropomórficos femininos e masculinos da serie FASH e MASH. Os resultados da dosimetria com filme radiocrômico mostraram valores da MDP variando de 180 a 5650 mGy; sendo que 40% dos pacientes apresentaram valores de dose na entrada da pele que ultrapassaram o limiar de dose para ocorrência de eritema transitório, que é de 2 Gy. O estudo das correlações entre a MDP, PKA e Ka,r mostrou que o Ka,r pode ser utilizado para avaliar a possibilidade de ocorrência de reações tissulares na pele dos pacientes submetidos a procedimentos de quimioembolização. Os resultados das simulações mostraram que alguns órgãos internos dos pacientes podem receber doses entre 500 mGy e 1 Gy. A dosimetria ocupacional foi realizada utilizando dosímetros termoluminescentes e dispositivos eletrônicos pessoais distribuídos em varias regiões do corpo dos profissionais. Os resultados mostraram que, com apenas uma quimioembolização por semana, o médico principal pode ultrapassar o limite anual de 20 mSv para o cristalino quando não são utilizados dispositivos de radioproteção como óculos ou telas de acrílico plumbíferos. O valor mais alto de equivalente de dose pessoal Hp(d) por procedimento medido no corpo do médico principal foi 5135,3 μSv no pé esquerdo. A ausência da cortina plumbífera durante a realização dos procedimentos é uma explicação para os valores altos registrados. Os valores médios de dose efetiva por procedimento para o médico principal, médico auxiliar e anestesista numa das instituições acompanhadas foram: 13 μSv, 6,1 μSv e 13,7 μSv, respectivamente. Estes resultados mostram que os níveis de exposição recebidos pelo anestesista em procedimentos de quimioembolização podem ser superiores aos do médico principal. Os resultados da dosimetria ocupacional com dosimetros eletrônicos mostraram que estes dispositivos podem ser utilizados de forma complementar na estimativa da dose ocupacional no cristalino em procedimentos de quimioembolização hepática. Nas seis instituições avaliadas observou-se uma alta variabilidade nos valores de dose no paciente e equipe médica, devido, principalmente, ao desempenho dos equipamentos, complexidade dos procedimentos, características físicas dos pacientes e experiência dos médicos. / Among interventional procedures, hepatic chemoembolization has been recognized as a complex procedure where high radiation doses to patients and medical staff are delivered. In some cases the patient has to endure several sessions to treat the same lesion, which increases even more the probability of skin injuries or stochastic effects. In Brazil, chemoembolization is widely used; however few dosimetric studies have been done so far. This study presents dosimetric results for medical staff and patients based on 109 hepatic chemoembolization procedures conducted in six hemodynamic departments in Recife, Pernambuco. The procedures were performed using digital angiography equipments from different manufacturers, using different technologies. Patient dosimetry comprised the measurement of the maximum skin dose (MSD), air kerma-area product (PKA) and reference air kerma (Ka,r). The MSD was measured using radiochromic films of type Gafchromic XR RV3. To assess the risk of stochastic effects, organ absorbed doses were calculated by Monte Carlo simulations using female and male anthropometric phantoms of the FASH and MASH series. MSDs between 180 and 5650 mGy were found based on the radiochromic film measurements. 40% of the patients monitored with radiochromic films received MSDs above the 2 Gy threshold for transient skin erythema. The findings of this study showed that the Ka,r can be used for risk estimates of tissue reactions in patients undergoing chemoembolization procedures. The Monte Carlo simulations showed that patients may receive organ doses between 500 mGy and 1 Gy. Occupational dosimetry was performed using thermoluminescent dosimeters and personal electronic devices distributed over various regions of the physician’s body. The results showed that the main operator could reach the annual limit of 20 mSv for the equivalent dose in the lens of the eyes with just one procedure per week if the radiation shields such as the ceiling suspended screen and goggles are not used. The highest values of personal dose equivalent Hp(d), measured in the body of the main operator was 5135.3 μSv in the left foot. Lack of table curtains explains the registered high values. Mean effective doses for the main operator, the auxiliary physician and the anesthesiologist in one of the institutions were 13 μSv, 6.1 μSv e 13.7 μSv, respectively. These results show that occupational doses received by the anesthesiologist in chemoembolization procedures may be higher than those received by the main operator. The results of the occupational dosimetry using electronic dosimeters showed that these devices can be used in a complementary way to estimate the occupational eye lens doses in hepatic chemoembolization procedures. High variability of radiation doses to patients and medical staff was observed among the six medical institutions, mainly because of the performance of X-ray equipments, complexity of the procedures, physical characteristics of the patients and the physician´s experience

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-04-26T12:16:51Z No. of bitstreams: 1 victorsylviosaggioro.pdf: 827982 bytes, checksum: 220854567786f428357cc808968543c7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-26T13:07:07Z (GMT) No. of bitstreams: 1 victorsylviosaggioro.pdf: 827982 bytes, checksum: 220854567786f428357cc808968543c7 (MD5) / Made available in DSpace on 2018-04-26T13:07:07Z (GMT). No. of bitstreams: 1 victorsylviosaggioro.pdf: 827982 bytes, checksum: 220854567786f428357cc808968543c7 (MD5) Previous issue date: 2015-12-05 / PROQUALI (UFJF) / Atualmente, o uso de técnicas para a correta identificação de indivíduos vivos ou mortos faz-se necessária para que este, ou sua família, possa usufruir dos direitos que lhe cabem e, assim, para que se possa buscar justiça nas sociedades a que pertencem. Os direitos mais fundamentais foram negados a um grupo significativos de pessoas durante os anos do regime de exceção vividos em nosso país. A negação, sobretudo, de conhecer as verdades dos fatos alcançou as famílias que não puderam enterrar ou desconhecem o paradeiro de seus entes presos e desaparecidos políticos da ditadura militar brasileira. Neste contexto que a antropologia forense figura como importante ferramenta para identificar restos mortais humanos. A dissertação buscou, a partir de pesquisa exploratória realizar um levantamento sobre a forma praticada pela pelos agentes da ditadura para desaparecer com as evidências dos crimes cometidos, mormente os corpos, e a aplicação da antropologia forense na identificação atual destes corpos exumados de valas comuns e covas clandestinas. Relata as dificuldades encontradas pela antropologia forense brasileira e a experiência do grupo argentino de antropólogos forenses. Por fim, reitera a importância da identificação dos mortos para trazer alentos às famílias e permitir eventual responsabilização do Estado. / Nowadays, the use of techniques for the identification of alive or dead is needed for this, or your family can enjoy the rights that fit you and thus, so that they can seek justice in the societies to which they belong. The most fundamental rights were denied to a significant group of people during the years of authoritarian regime lived in our country. Denial, above all, know the truths of the events reached the families who were unable to bury or unaware of the whereabouts of their loved political prisoners and missing the Brazilian military dictatorship. In this context that the forensic anthropology appears as an important tool to identify the human remains. The dissertation sought, from exploratory research to survey the form practiced by the dictatorship of agents to disappear with the evidence of the crimes committed, especially the bodies and the application of forensic anthropology in the current identification of these bodies exhumed from mass graves and clandestine graves. Recounts the difficulties encountered by Brazilian forensic anthropology and experience of the Argentine group of forensic anthropologists. Finally, it reiterates the importance of identifying the dead to bring breaths families and allow potential liability of the state.

Cette thèse a été réalisée dans le cadre de la dosimétrie des faisceaux de haute énergie délivrés au patient pendant un traitement de radiothérapie externe. L'objectif de ce travail est de vérifier que la distribution de dose 3D absorbée dans le patient est conforme au calcul réalisé sur le système de planification de traitement (TPS) à partir de l'imageur portal (en anglais : Electronic Portal Imaging Device, EPID). L'acquisition est réalisée en mode continu avec le détecteur aS-1200 au silicium amorphe embarqué sur la machine TrueBeam STx (VARIAN Medical system, Palo Alto, USA). Les faisceaux ont une énergie de 10 MeV et un débit de 600 UM.min-1. La distance source-détecteur (DSD) est de 150 cm. Après correction des pixels défectueux, une étape d'étalonnage permet de convertir leur signal en dose absorbée dans l'eau via une fonction de réponse. Des kernels de correction sont également utilisés pour prendre en compte la différence de matériaux entre l'EPID et l'eau et pour corriger la pénombre sur les profils de dose. Un premier modèle de calcul a permis ensuite de rétroprojeter la dose portale en milieu homogène en prenant en compte plusieurs phénomènes : les photons diffusés provenant du fantôme et rajoutant un excès de signal sur les images, l'atténuation des faisceaux, la diffusion dans le fantôme, l'effet de build-up et l'effet de durcissement du faisceau avec la profondeur. La dose reconstruite est comparée à celle calculée par le TPS avec une analyse gamma globale (3% du maximum de dose et 3 mm de DTA). L'algorithme a été testé sur un fantôme cylindrique homogène et sur un fantôme de pelvis à partir de champs modulés en intensité (RCMI) et à partir de champs d'arcthérapie volumique modulés, VMAT selon l'acronyme anglais Volumetric Modulated Arc Therapy. Le modèle a ensuite été affiné pour prendre en compte les hétérogénéités traversées dans le milieu au moyen des distances équivalentes eau dans une nouvelle approche de dosimétrie plus connue sous le terme de " in aqua vivo " (1). Il a été testé sur un fantôme thorax et, in vivo sur 10 patients traités pour une tumeur de la prostate à partir de champs VMAT. Pour finir, le modèle in aqua a été testé sur le fantôme thorax avant et après y avoir appliqué certaines modifications afin d'évaluer la possibilité de détection de sources d'erreurs pouvant influencer la bonne délivrance de la dose au patient.[...] / This thesis aims at the dosimetry of high energy photon beams delivered to the patient during an external radiation therapy treatment. The objective of this work is to use EPID the Electronic Portal Imaging Device (EPID) in order to verify that the 3D absorbed dose distribution in the patient is consistent with the calculation performed on the Treatment Planning System (TPS). The acquisition is carried out in continuous mode with the aS-1200 amorphous silicon detector embedded on the TrueBeam STx machine (VARIAN Medical system, Palo Alto, USA) for 10MV photons with a 600 UM.min-1 dose rate. The source-detector distance (SDD) is 150 cm. After correction of the defective pixels, a calibration step is performed to convert the signal into an absorbed dose in water via a response function. Correction kernels are also used to take into account the difference in materials between EPID and water and to correct penumbra. A first model of backprojection was performed to reconstruct the absorbed dose distribution in a homogeneous medium by taking into account several phenomena: the scattered photons coming from the phantom to the EPID, the attenuation of the beams, the diffusion into the phantom, the build-up, and the effect of beam hardening with depth. The reconstructed dose is compared to the one calculated by the TPS with global gamma analysis (3% as the maximum dose difference criteria and 3mm as the distance to agreement criteria). The algorithm was tested on a homogeneous cylindrical phantom and a pelvis phantom for Intensity-Modulated Radiation Therapy (IMRT) and (Volumetric Arc Therapy (VMAT) technics. The model was then refined to take into account the heterogeneities in the medium by using radiological distances in a new dosimetrical approach better known as "in aqua vivo" (1). It has been tested on a thorax phantom and, in vivo on 10 patients treated for a prostate tumor from VMAT fields. Finally, the in aqua model was tested on the thorax phantom before and after making some modifications to evaluate the possibility of detecting errors that could affect the correct delivery of the dose to the patient. [...]

L’incidence de l’ischémie critique est en augmentation depuis ces vingt dernières années. La revascularisation diminue le taux d’amputation. Les plaies ischémiques infectées avec l’exposition des tendons, des os ou des articulations, ne peuvent pas cicatriser avec la revascularisation et le débridement local. La chirurgie, associant un pontage veineux distal ou une recanalisation et un lambeau libre, permet de traiter les pertes de substances et présente un avantage hémodynamique en augmentant le débit du pontage grâce au lit vasculaire ajouté par le lambeau. Nous proposons une nouvelle technique chirurgicale basée sur l’utilisation d’une unité anatomique unique, le lambeau-pontage épiploïque (LPE). Il est composé d’un axe artériel, l’artère gastroépiploïque (AGE), qui procure le greffon, et du grand épiploon, utilisé comme lambeau irrigué par une ou plusieurs branches épiploïques. Le but de ce travail était d’analyser la faisabilité anatomique d’un LPE et de valider le scanner pour l’évaluation préopératoire de l’AGE. Nous avons également évalué les effets hémodynamiques de cette technique et analysé la première expérience clinique. 100 dissections anatomiques ont été réalisées afin de mesurer les diamètres et les longueurs de l’AGE droite et de ses branches, ainsi qu’une radiographie après injection de produit radio-opaque. Pour évaluer la faisabilité préopératoire, nous avons étudié 30 tomodensitométries. Nous avons également exploré les effets hémodynamiques dans le modèle porcin. Notre étude anatomique confirme la faisabilité d’un LPE. La longueur moyenne de l’AGE est de 24,5 cm. Le diamètre proximal moyen est de 3 mm et celui distal est de 1,5 mm. Les données de l’étude radiologique montrent que le scanner peut être utilisé pour le repérage préopératoire de l’AGE et la faisabilité d’un LPE. Les mesures hémodynamiques ont montré que, grâce au lambeau épiploïque, le débit sanguin du pontage augmente et que les résistances distales diminuent. Le LPE est une technique chirurgicale qui doit permettre de repousser les limites de sauvetage de membre dans les conditions de cette pathologie extrême, réalisant une revascularisation distale et une couverture simultanée des pertes de substances chez les patients atteints d’artériopathie. / The incidence of critical limb ischemia increases with the ageing of the population. Often, revascularization decreases the rate of amputation. In some cases, infected wounds with exposure of the tendons, bones or articulations will not heal only with revascularization and local debridement. Surgery combining a distal venous bypass or recanalisation and a free flap can treat those wounds, the vascular bed added by the flap improve the hemodynamic and increases the flow in the bypass. We proposed a new surgical method based on the use of a single anatomical unit, the epiploic flow-through flap (FTF), the gastroepiploic artery (GEA) as the vascular substitute and the greater omentum as the flap. The aim of this work was to analyze the anatomical feasibility of an epiploic BF, and to validate CT scan for preoperative assessment of the suitability of the GEA. We also aimed to evaluate the hemodynamic effects of this technique and to analyze the first clinical experience. 100 anatomical dissections were performed in order to measure the diameters and the lengths of GEA and its branches. An extensive X-ray study was also carried out with injection of a radiopaque product. To evaluate preoperative feasibility of the omental FTF, we studied radiological properties of the GEA on 30 routine CT scans. Finally, we also explored the hemodynamic behavior of this artery and its related flap in porcine models. Our anatomical study confirms the feasibility of a FTF. The average available length of GEA is 245 mm. The average proximal diameter is 3 mm and the distal one is 1.5 mm. Data of radiological study show that CT scan can be used to indicate GEA suitability for an epiploic FTF. The hemodynamic measures showed that thanks to the flap, the blood flow increase in the bypass. Ultimately,we report our first clinical application of the omental FTF for distal lower limb revascularization combined to wound coverage, with successful outcome. Epiploic FTF is a surgical technique, which allows distal revascularization and a simultaneous cover of the limb extremity. This technique can be useful in patients requiring a distal revascularization associated with the coverage of large the wounds

The aim of this diploma thesis is to clarify fundamental principles of activities of police officers of the Regional Directorate of the Police of the South Bohemian Region in the case of radiological emergency at the Temelín Nuclear power station. These principles are concentrated in compact documentation with practical tasks for respective organizational segments of the Regional Directorate of the Police of the South Bohemian Region. This documentation will be consequently used as a methodical guide for concerned police officers. Fundamental terms are defined in the theoretical part of the diploma thesis, concerning and usable in the course of measures in the case of solving radiological emergency at the Temelín Nuclear power station. The analysis of legal standards and technical bibliography is also performed in this part. The External Emergency Plan of the Temelín Nuclear power station is presented in detail, and a comparison of the previous and current atomic law is drawn. Last chapter of this part is devoted to the actual documentation of the Regional Directorate of the Police of the South Bohemian Region to manage the radiological emergency at the Temelín Nuclear power station. Necessary number of legal regulations, agreements and internal acts of management concerning the current topic was used for elaboration of this thesis. Information and findings of employees from the Department of Emergency Management of the Regional Directorate of the Police of the South Bohemian Region are also included. The practical part of the diploma thesis is devoted to the concentration of all materials and previous findings of the Regional Directorate of the Police of the South Bohemian Region in the case of measures for radiological emergency at the Temelín Nuclear power station into individual chapters. Each of these chapters presents particular activities of police officers of the Regional Directorate of the Police of the South Bohemian Region during performation of tasks in connection with managing the radiological emergency at the Temelín Nuclear power station. When listing particular tasks and processes, some of activities of other subjects participating together with members of the Police of the Czech Republic in measures concerning the radiological emergency are also mentioned in this part. The result of this thesis is a focused overview and operative material for police officers of the Police of the Czech Republic, usable for making them acquainted with questions of managing the radiological emergency at the Temelín Nuclear power station. It also serves as a background for regular practices and training courses on this subject.

Pour certaines maladies causées par des agents chimiques, biologiques, radiologiques et nucléaires (CBRN), il n’existe pas de contre-mesures médicales (MedCM) et bon nombre de celles qui existent pourraient ne pas être disponibles en cas de besoin. En cas d’accident CBRN, des efforts inadéquats de financement de la R&D et de mise à disposition par les gouvernements peuvent avoir de graves conséquences économiques nettement supérieures aux coûts d’initiatives préventives. Compte-tenu des contraintes budgétaires auxquelles de nombreux gouvernements sont confrontés, il est nécessaire de définir des priorités. Parallèlement à la mise en place d’indicateurs de décision de santé efficaces qui identifient et mesurent les effets de causalité de l’impact négatif sur la santé, le processus de décision doit également prendre en considération le rapport coût-efficacité pour rendre le financement durable.Cette thèse a pour objectif de définir une voie vers une politique économique de santé publique visant à renforcer la disponibilité des MedCM pour les agents CBRN. Dans la première partie, les causes des défaillances du marché sont identifiées (lorsque les opportunités de profit ne compensent pas l’effort de R&D nécessaire). Dans la deuxième partie, des études de cas illustrent les caractéristiques et les conséquences économiques d’exemples d’accidents CBRN et des scénarios sont analysés afin de mettre en évidence comment la disponibilité de MedCM pourrait potentiellement devenir rentable. Enfin, la troisième partie propose des approches plus complètes pour mesurer et compenser les facteurs contribuant à la défaillance du marché en appliquant des modèles économiques spécifiques. / For some diseases caused by chemical, biological, radiological, and nuclear (CBRN) agents, innovative medical countermeasures (MedCMs) do not exist while many of those that do might not be readily available. In case of a CBRN event, inappropriate medical research and development (R&D) funding and government procurement efforts can result in adverse economic consequences (e.g. lost income) far exceeding the costs of strong and comprehensive preparedness initiatives. Given the budgetary constraints many governments face, priorities must be defined. Parallel to determining effective health decision metrics that identify and weigh the causal effects of negative health impact, decision making must also consider cost-effectiveness to make funding sustainable. Moreover, international cooperation is necessary since the risks increasingly transcend borders due to global travel and the global threat of terrorism. This dissertation ultimately seeks to define a path to public health economic policy to enhance the international availability of CBRN MedCMs. In Part I, the root causes of market failure are identified and depicted (i.e., where rewards for supply do not adequately compensate for the R&D effort). In Part II, case study examples illustrate the characteristics and economic consequences of CBRN incidents. Scenarios for each case are outlined to show where the availability of MedCMs in these situations could potentially be cost-effective. Finally, Part III construes more comprehensive approaches for gauging and offsetting the deterrence factors of market supply and demand by compiling and applying additional economic models and frameworks.

Early detection is vital to successfully treating breast cancer, and mammography screening is the most efficient and wide-spread method to reach this goal. Imaging low-contrast targets, while minimizing the radiation exposure to a large population is, however, a major challenge. Optimizing the image quality per unit radiation dose is therefore essential. In this thesis, two optimization schemes with respect to x-ray photon energy have been investigated: filtering the incident spectrum with refractive x-ray optics (spectral shaping), and utilizing the transmitted spectrum with energy-resolved photon-counting detectors (spectral imaging). Two types of x-ray lenses were experimentally characterized, and modeled using ray tracing, field propagation, and geometrical optics. Spectral shaping reduced dose approximately 20% compared to an absorption-filtered reference system with the same signal-to-noise ratio, scan time, and spatial resolution. In addition, a focusing pre-object collimator based on the same type of optics reduced divergence of the radiation and improved photon economy by about 50%. A photon-counting silicon detector was investigated in terms of energy resolution and its feasibility for spectral imaging. Contrast-enhanced tumor imaging with a system based on the detector was characterized and optimized with a model that took anatomical noise into account. Improvement in an ideal-observer detectability index by a factor of 2 to 8 over that obtained by conventional absorption imaging was found for different levels of anatomical noise and breast density. Increased conspicuity was confirmed by experiment. Further, the model was extended to include imaging of unenhanced lesions. Detectability of microcalcifications increased no more than a few percent, whereas the ability to detect large tumors might improve on the order of 50% despite the low attenuation difference between glandular and cancerous tissue. It is clear that inclusion of anatomical noise and imaging task in spectral optimization may yield completely different results than an analysis based solely on quantum noise. / QC 20100714

No description available.

Made available in DSpace on 2014-12-17T15:47:46Z (GMT). No. of bitstreams: 1 FrederikoSLNA.pdf: 5281687 bytes, checksum: 9fe12b6bcc355f7c67cf2f2c3ad9812b (MD5) Previous issue date: 2006-02-16 / This work performs an algorithmic study of optimization of a conformal radiotherapy plan treatment. Initially we show: an overview about cancer, radiotherapy and the physics of interaction of ionizing radiation with matery. A proposal for optimization of a plan of treatment in radiotherapy is developed in a systematic way. We show the paradigm of multicriteria problem, the concept of Pareto optimum and Pareto dominance. A generic optimization model for radioterapic treatment is proposed. We construct the input of the model, estimate the dose given by the radiation using the dose matrix, and show the objective function for the model. The complexity of optimization models in radiotherapy treatment is typically NP which justifyis the use of heuristic methods. We propose three distinct methods: MOGA, MOSA e MOTS. The project of these three metaheuristic procedures is shown. For each procedures follows: a brief motivation, the algorithm itself and the method for tuning its parameters. The three method are applied to a concrete case and we confront their performances. Finally it is analyzed for each method: the quality of the Pareto sets, some solutions and the respective Pareto curves / O presente trabalho realiza um Estudo Algor?tmico para Otimiza??o do Plano de Tratamento da Radioterapia Conformal. Inicialmente s?o apresentadas: uma vis?o geral sobre o c?ncer, o tratamento com radioterapia e no??es sobre a intera??o do feixe de radia??es ionizantes com a mat?ria. Uma proposta para Otimiza??o do Plano de Tratamento Radioter?pico ? desenvolvida de modo sistem?tico. ? apresentado o paradigma de problemas multicrit?rio, os conceitos de Pareto otimalidade e Pareto Domin?ncia. Um modelo Gen?rico de Otimiza??o para o Plano de Tratamento Radioter?pico ? proposto. S?o constru?das suas entradas, ? calculada a dose depositada no corpo do paciente atrav?s do conceito de matriz de dose, e ? apresentada a fun??o objetivo deste modelo. A complexidade dos problemas de otimiza??o do tratamento radioter?pico s?o classificados como de complexidade NP, este resultado justifica o desenvolvimento de m?todos heur?sticos para a sua resolu??o. S?o propostas tr?s metaheur?sticas para a Otimiza??o do Plano de Tratamento Radioter?pico: MOGA, MOSA e MOTS de acordo como o modelo gen?rico de otimiza??o proposto. Os projetos desses procedimentos metaheur?sticos s?o devidamente apresentados. Para cada m?todo se faz uma introdu??o liter?ria, dos seus algoritmos e a da metodologia usada para a afina??o dos par?metros. Os m?todos s?o aplicados a um caso concreto e confrontados atrav?s de medidas de performance. Finalmente ? analisado a qualidade dos conjuntos de Pareto produzidos por cada m?todo, s?o exibidas algumas solu??es geradas e as respectivas curvas de Pareto associadas

Text in English / The contribution of general diagnostic imaging in the diagnosis and clinical management of patients in rural hospitals of South Africa is enormous. To provide high quality diagnostic imaging services for specific contexts requires radiographers who have up-to-date skills and expertise. Thus, rural radiographers require, over and above traditional radiographic expertise, additional competencies which are unique to rural practice. To date, however, little is known about additional core competencies and skills needed by radiographers working in rural areas. Previous studies have focused more attention primarily on other rural health professionals such as doctors and nurses. The aim of this mixed methods study was to investigate and identify additional core competencies required by radiographers working in rural district hospitals of KZN in order to propose a CPD strategy aimed at rural radiographers. An exploratory sequential design was utilised. There were seven participants in the qualitative phase of the study. In the quantitative phase a convenient sample of 109 respondents was surveyed using a structured questionnaire. Three major themes and seven categories emerged from Phase I of the study. These themes and categories were then used to develop a data collection instrument for Phase II of the study. Collectively, the findings of this mixed methods research revealed that there were a number of additional core competencies such as, but not limited to, teamwork, ability to do basic obstetric ultrasound scans, leadership, management, attitude and behaviours, and reporting on plain x-ray films, all of which are required by rural radiographers. Supporting evidence from the study indicated that the majority of these competencies were either partially or not at all covered in the audited curriculum. The study further revealed that the audited curriculum and the scope of radiography in its current form appear to focus attention on minimum competencies that do not promote the expansion and extension of the role of radiographers in rural areas. The study results also revealed a number of challenges faced by rural radiographers. / Health Studies / D. Litt. et Phil. (Health Studies)