A osteoporose é uma epidemia mundial, exprime altas taxas de morbidade e mortalidade, resultando também em altos custos sociais. O exame de densitometria óssea por dupla emissão de raios-X (DXA) é o exame padrão ouro para o diagnóstico da doença, porém a baixa disponibilidade de equipamentos e o alto custo dificultam o acesso ao exame, principalmente nos países pobres e nos emergentes. Desta forma absorciometria radiografica da falange (AR) se destaca pois tem baixa dose de radiação, é mais simples utilizando apenas uma radiografia de mão e um software. A radiografia panorâmica é amplamente utilizada na rotina do atendimento odontológico no mundo todo, e tem sido estudada para a avaliação de pacientes com baixa densidade mineral óssea (DMO). O objetivo deste estudo foi correlacionar a qualidade óssea mandibular, por meio dos índices radiomorfométricos em radiografia panorâmica, com a qualidade óssea das falanges da mão não dominante, por meio da AR. A amostra constituiu-se por 167 pacientes (128 mulheres e 39 homens) com média de idade de 52.09 (± 11.5) divididos em quatro grupos de acordo com o exame AR: Mulheres Normais (MN) com 92; Mulheres Doentes (MD) com 36; Homens Normais (HN) com 25; e Homens Doentes (HD) com 14.9. Os resultados demonstraram que houve correlação (p<0.00037) entre a classificação de Klemetti com a AR. A análise de variância de IM, IG, IFM, IFP apresentaram diferenças significativas (p <0.05) entre os grupos comparados. A área encontranda sob a curva ROC foi de 0.74 (SE = 97.4%, ES= 78%) para IM, 0.79 (SE = 94, ES= 54%) para IG, 0.77 (SE =94.8%, ES= 64%) para IFM, 0.76 (SE= 93,1%, ES= 62%) para IFP, 0.71(SE =96.5%, ES 86%) para DF. Concluiu-se que a análise dos índices radiomorfométricos apresentaram acurácia moderadamente precisa para a detecção da alteração na qualidade óssea mandibular de acordo com a AR. / Osteoporosis is a worldwide epidemic, expressed high rates of morbidity and mortality, also resulting in high social costs. Bone densitometry by dual energy X-ray absorptiometry (DXA) is gold standard for the diagnosis of disease, but the low availability of equipment and high costs make it difficult to take, especially in poor and emerging countries. Thus absorptiometry radiographically phalanx (AR) stands out because has low radiation dose, it is simpler using only one hand X-ray and software. Panoramic radiography is widely used in routine dental care worldwide, and has been studied for the evaluation of patients with low bone mineral density (BMD).The aim of this study was to correlate the mandibular bone quality through radiomorphometric indices in panoramic radiograph with bone quality of the non-dominant hand phalanges, through AR. The sample consisted of 167 patients (128 women and 39 men) with a mean age of 52.09 (± 11.5) divided into four groups according to the AR test: Healthy Women (MN) 92; Diseased Women (MD) 36; Men healthy (HN) 25 and Diseased Men (HD) with 14.9. The results showed correlation (p <0.00037) between the Klemetti with RA. Variance analysis IM, IG, MFIs, IFP shown significant differences (p <0.05) between the two groups. Area under the ROC curve was 0.74 (SE = 97.4%, ES = 78%) for MI, 0.79 (SE = 94, ES = 54%) for IG, 0.77 (SE = 94.8%, ES = 64%) for MFIs, 0.76 (SE = 93.1%, ES = 62%) for IFP, 0.71 (SE = 96.5%, ES 86%) for DF. It was concluded that the analysis of radiomorphometric indices showed moderate accuracy for detecting the change in mandibular bone quality according to AR.

Bakgrund: Antalet bilddiagnostiska undersökningar ökar. Behov finns att implementera riktlinjer för remisser till röntgenavdelningen. 20% av alla DT undersökningar bedöms inte vara berättigade. Under 2017 inleddes översättning till lokala förhållanden och implementering av iGuide på försök i en av Sveriges regioner. Syfte: Syftet är att studera röntgensjuksköterskors- och radiologers erfarenheter från berättigande av undersökningar på röntgenavdelningen. Metod: En empirisk studie med kvalitativ design. En induktiv ansats tillämpades. Semistrukturerade intervjuer utfördes med legitimerade radiologer och röntgensjuksköterskor. Intervjumaterialet analyserades med en manifest innehållsanalys. Resultat: Innehållsanalysen mynnade ut i följande subkategorier:  Innebörden av berättigande, Ansvarsfördelning vid berättigande, Oberättigade remisser och åtgärder, Remittent och patient inverkar på berättigandet, Organisationen inverkar på berättigandet, Tillgänglighet av olika modaliteter inverkar på berättigandet, IGuide är grundat i problemen med berättigande, samt Resultatet från iGuide-projektet. Subkategorierna bildar tre kategorier: Berättigande av undersökningar, Förekomst av oberättigade undersökningar, samt iGuide som ett sätt att uppnå ökat berättigande. Slutsats: Röntgenutnyttjandet ökar och därmed problemen med berättigande. Radiologerna upplever att brist på tid påverkar berättigandet negativt, också att remittenten ofta har svårt att neka patienter. Röntgensjuksköterskor upplever att kommunikationen avdelningar emellan är viktig för berättigande. Det ökade utbudet av modaliteter beskrivs påverka. IGuide ökar andelen berättigade undersökningar, och minskar antalet begärda bilddiagnostiska undersökningar, men systemet behöver få en ökad användarvänlighet. / Background:  The number of image diagnostic examinations is increasing. There is a need to implement guidelines for referrals to the X-ray department. 20% of all DT examinations are deemed not to be justified. In 2017, implementation and translation into local conditions of iGuide in trial was initiated in one of Sweden's regions. The aim: The aim is to study the experiences of radiographers and radiologists from the justification of examinations in the X-ray department. Method:  An empirical study with qualitative design. The inductive approach was applied. Semi-structured interviews were applied with licensed radiographers and radiologist. The interview material was analyzed with a manifesto content analysis.  Results:  The analysis resulted in the following subcategories: The meaning of justification, The shared responsibility in justification, Unjustified referrals and actions, Remittent and patient impact on justification, The organization impact on justification, The accessibility of various modalities affect justification, IGuide is based on the problems of justification, and The results of the iGuide-project. The subcategories form three categories: Justification of examinations, Existence of unjustified examinations, and IGuide as a means of achieving increased justification. Conclusion:  X-ray utilization is increasing and thus the problems with justification. The radiologists experience that the lack of time affects justification negatively, also that the remittance often has difficulty in denying patients. Radiographers experience that communication between departments is important for justification. The increased range of modalities is described as affecting. IGuide increases the proportion of justified examinations, and reduces the number of requested imaging examinations, but the system needs to be given a greater user-friendliness.

<p> Some experiments designed to test the validity of the edge-spread function (ESF) model for neutron radiographic image formation are described; in addition the experiments are meant to illustrate the application of ESF methods to two areas of practical concern. First, the prediction of optical density curves for specified material and geometric configurations is considered; then, the use of ESF methods in dimensioning irradiated reactor fuel elements is examined. Overall, the results indicate that within the framework of assumptions which ESF theory is based upon, the correlation between theory and experiment is excellent. The results also suggest that in situations which deviate from the theoretical ideal, the ESF method may serve as a good first approximation to more complex models. </p> / Thesis / Master of Engineering (ME)

Doctor of Philosophy / Radiographic film/screen (F/S) images have a narrow latitude or dynamic range. The film’s ability to record and view all the anatomy within the x-ray field is limited by this narrow dynamic range. The advent of digital radiographic means of storing and displaying radiographic images has improved the ability to record and visualise all of the anatomy. The problem still exists in digital radiography (DR) when radiographic examinations of certain anatomical regions are undertaken. In this work, the value of anatomically shaped radiographic contrast-enhancement masks (RCMs) in improving image contrast and reducing the dynamic range of images in DR was examined. Radiographic contrast-enhancement masks are digital masks that alter the radiographic contrast in DR images. The shape of these masks can be altered by the user. Anatomically shaped RCMs have been modelled on tissue compensation filters (TCFs) commonly used in F/S radiographic examinations. The prime purpose of a TCF is to reduce the dynamic range of photons reaching the image receptor and hence improve radiographic contrast in the resultant image. RCMs affect the dynamic range of the image rather than the energy source of the image, that of the x-ray photons. The research consisted of three distinct phases. The first phase was to examine physical TCFs and their effects on F/S radiographic images. Physical TCFs are used in radiographic F/S examinations to attenuate the x-ray beam to compensate for varying patient tissue thicknesses and/or densities. The effect of the TCF is to reduce resultant radiographic optical density variations in the image, allowing the viewer to observe a range of densities within the image which would otherwise not be visualised. Physical TCFs are commonly aluminium- or lead-based materials that attenuate the x-ray beam. A TCF has varying physical thickness to differentially attenuate the iii beam and is shaped for specific anatomical situations. During this project, various commonly used physical TCFs were examined. Measurements of size and thickness were made. Characteristics of linear attenuation coefficients and half-value thicknesses were delineated for various TCF materials and at various energies. The second phase of the research was to model the physical TCFs in a digital environment and apply the RCMs to DR images. The digital RCMs were created with similar characteristics to mimic the shapes to the physical TCFs. The RCM characteristics can be adjusted by the viewer of the image to suit the anatomy being imaged. Anatomically shaped RCMs were designed to assist in overcoming a limitation when viewing digital radiographic images, that of the dynamic range of the image. Anatomically shaped RCMs differ from other means of controlling the dynamic range of a digital radiographic image. It has been shown that RCMs can reduce the range of optical densities within images with a large dynamic range, to facilitate visualisation of all anatomy within the image. Physical TCFs are used within a specific range of radiographic F/S examinations. Digital radiographic images from this range of examinations were collected from various clinical radiological centres. Anatomically shaped RCMs were applied to the images to improve radiographic contrast of the images. The third phase of the research was to ascertain the benefits of the use of RCMs. Various other methods are currently in use to reduce the dynamic range of digital radiographic images. It is generally accepted that these methods also introduce noise into the image and hence reduce image quality. Quantitative comparisons of noise within the image were undertaken. The anatomically shaped RCMs introduced less noise than current methods designed to reduce the dynamic range of digital radiographic images. It was shown that RCM methods do not affect image quality. Radiographers make subjective assessment of digital radiographic image quality as part of their professional practice. To assess the subjective quality of images enhanced with anatomically shaped RCMs, a survey of radiographers and other iv qualified people was undertaken to ascertain any improvement in RCM-modified images compared to the original images. Participants were provided with eight pairs of image to compare. Questions were asked in the survey as to which image had the better range of optical densities; in which image the anatomy was easiest to visualise; which image had the simplest contrast and density manipulation for optimal visualisation; and which image had the overall highest image quality. Responses from 123 participants were received and analysed. The statistical analysis showed a higher preference by radiographers for the digital radiographic images in which the RCMs had been applied. Comparisons were made between anatomical regions and between patient-related factors of size, age and whether pathology was present in the image or not. The conclusion was drawn that digital RCMs correctly applied to digital radiographic images decrease the dynamic range of the image, allowing the entire anatomy to be visualised in one image. Radiographic contrast in the image can be maximised whilst maintaining image quality. Using RCMs in some digital radiographic examinations, radiographers will be able to present optimised images to referring clinicians. It is envisaged that correctly applied RCMs in certain radiographic examinations will enhance radiographic image quality and possibly lead to improved diagnosis from these images.

Doctor of Philosophy / Radiographic film/screen (F/S) images have a narrow latitude or dynamic range. The film’s ability to record and view all the anatomy within the x-ray field is limited by this narrow dynamic range. The advent of digital radiographic means of storing and displaying radiographic images has improved the ability to record and visualise all of the anatomy. The problem still exists in digital radiography (DR) when radiographic examinations of certain anatomical regions are undertaken. In this work, the value of anatomically shaped radiographic contrast-enhancement masks (RCMs) in improving image contrast and reducing the dynamic range of images in DR was examined. Radiographic contrast-enhancement masks are digital masks that alter the radiographic contrast in DR images. The shape of these masks can be altered by the user. Anatomically shaped RCMs have been modelled on tissue compensation filters (TCFs) commonly used in F/S radiographic examinations. The prime purpose of a TCF is to reduce the dynamic range of photons reaching the image receptor and hence improve radiographic contrast in the resultant image. RCMs affect the dynamic range of the image rather than the energy source of the image, that of the x-ray photons. The research consisted of three distinct phases. The first phase was to examine physical TCFs and their effects on F/S radiographic images. Physical TCFs are used in radiographic F/S examinations to attenuate the x-ray beam to compensate for varying patient tissue thicknesses and/or densities. The effect of the TCF is to reduce resultant radiographic optical density variations in the image, allowing the viewer to observe a range of densities within the image which would otherwise not be visualised. Physical TCFs are commonly aluminium- or lead-based materials that attenuate the x-ray beam. A TCF has varying physical thickness to differentially attenuate the iii beam and is shaped for specific anatomical situations. During this project, various commonly used physical TCFs were examined. Measurements of size and thickness were made. Characteristics of linear attenuation coefficients and half-value thicknesses were delineated for various TCF materials and at various energies. The second phase of the research was to model the physical TCFs in a digital environment and apply the RCMs to DR images. The digital RCMs were created with similar characteristics to mimic the shapes to the physical TCFs. The RCM characteristics can be adjusted by the viewer of the image to suit the anatomy being imaged. Anatomically shaped RCMs were designed to assist in overcoming a limitation when viewing digital radiographic images, that of the dynamic range of the image. Anatomically shaped RCMs differ from other means of controlling the dynamic range of a digital radiographic image. It has been shown that RCMs can reduce the range of optical densities within images with a large dynamic range, to facilitate visualisation of all anatomy within the image. Physical TCFs are used within a specific range of radiographic F/S examinations. Digital radiographic images from this range of examinations were collected from various clinical radiological centres. Anatomically shaped RCMs were applied to the images to improve radiographic contrast of the images. The third phase of the research was to ascertain the benefits of the use of RCMs. Various other methods are currently in use to reduce the dynamic range of digital radiographic images. It is generally accepted that these methods also introduce noise into the image and hence reduce image quality. Quantitative comparisons of noise within the image were undertaken. The anatomically shaped RCMs introduced less noise than current methods designed to reduce the dynamic range of digital radiographic images. It was shown that RCM methods do not affect image quality. Radiographers make subjective assessment of digital radiographic image quality as part of their professional practice. To assess the subjective quality of images enhanced with anatomically shaped RCMs, a survey of radiographers and other iv qualified people was undertaken to ascertain any improvement in RCM-modified images compared to the original images. Participants were provided with eight pairs of image to compare. Questions were asked in the survey as to which image had the better range of optical densities; in which image the anatomy was easiest to visualise; which image had the simplest contrast and density manipulation for optimal visualisation; and which image had the overall highest image quality. Responses from 123 participants were received and analysed. The statistical analysis showed a higher preference by radiographers for the digital radiographic images in which the RCMs had been applied. Comparisons were made between anatomical regions and between patient-related factors of size, age and whether pathology was present in the image or not. The conclusion was drawn that digital RCMs correctly applied to digital radiographic images decrease the dynamic range of the image, allowing the entire anatomy to be visualised in one image. Radiographic contrast in the image can be maximised whilst maintaining image quality. Using RCMs in some digital radiographic examinations, radiographers will be able to present optimised images to referring clinicians. It is envisaged that correctly applied RCMs in certain radiographic examinations will enhance radiographic image quality and possibly lead to improved diagnosis from these images.

The purpose of this study was to compare three direct digital sensors (Kodak 6100, Schick CDR, and Dexis PerfectSize), a phosphor plate system (OpTime), and F-speed film to standard D-speed film in the detection of artificial bone lesions prepared in mandible bone sections. Multiple artificial bone lesions were prepared at varying depths in the cortical bone. Specimens were imaged with six different radiographic systems. Radiographs were randomly presented to nine different observers. A logistic regression analysis indicated that the ability of the different radiographic systems to detect the bone lesions was significantly different at the mean percentage of cortical bone remaining. The Kodak filtered, Schick filtered, OpTime unfiltered, Schick unfiltered, and Dexis filtered images were significantly better at lesion detection compared to D-speed film. Also, all filtered digital images were significantly better at lesion detection than D-speed film.

Desde a introdução dos implantes na Odontologia, controvérsias tem havido acerca da propriedade de conectar os implantes a dentes em próteses fixas. Os implantes osseointegrados não apresentam nenhum ligamento periodontal e são mais firmemente ancorados ao osso. A diferença apresentada nesta ancoragem tem levantado preocupações acerca de o implante osseointegrado, por sua firme fixação ao osso, apresentar pouca flexibilidade para dividir as cargas funcionais com os dentes conectados. O presente estudo teve como propósito acompanhar prospectivamente os parâmetros periodontais ? índice gengival, índice de sangramento, profundidade de sondagem e perda de inserção entre o dente pilar de uma prótese dento-implanto-suportada com o dente colateral do mesmo paciente, e também os parâmetros peri-implantares dos implantes que suportam estas próteses - índice gengival; índice de sangramento; profundidade de sondagem e perda de inserção. Para verificar a perda de inserção foi utilizado o recurso da subtração radiográfica da região em que a prótese foi instalada, com tomadas radiográficas efetuadas no momento da instalação da prótese, decorridos seis meses e após 12 meses de uso, com o objetivo de verificar a ocorrência, ou não, de alteração do suporte ósseo peri-implantar. Foram selecionados 12 pacientes com estado de saúde normal, apresentando área posterior de mandíbula edêntula onde estava indicada a reabilitação protética por meio de prótese fixa unindo dente a implante. Estes foram tratados com implante de um estágio de 10 mm padrão da Straumann (ITI), que apresenta um pescoço polido de 2.8mm, onde a porção do implante que permanece intra-óssea apresenta uma superfície tratada, com diâmetro de 4.1mm. O implante foi instalado no espaço onde se localizaria o retentor mais distal da futura prótese parcial fixa, seguindo o protocolo. As radiografias digitais obtidas foram avaliadas num software de subtração radiográfica, Matrox Inspector versão oito, para verificar a alteração da variação de densidade óptica e contraste das radiografias quando superpostas, sendo os valores observados no implante comparados com os critérios de sucessos , amplamente abordados nos estudos verificados. Todos os implantes instalados nos pacientes osseointegraram, não houve registro de alteração óssea ao redor dos mesmos e nos dentes pilares das próteses em avaliações feitas após seis meses e 12 meses. As próteses continuaram clinicamente em excelente estado após 12 meses de avaliação nas análises clínicas e radiográficas. Ainda, de acordo com o teste de Sinais de Postos de ilcoxon, concluiu-se estatisticamente que não houve diferença nos parâmetros peri-implantares de cada paciente durante os períodos analisados (zero, seis meses e 12 meses), bem como quando comparados com os respectivos dentes colaterais. / Since the introduction of implants in Dentistry, controversies have arisen about the possibility of connecting implants to teeth in fixed prostheses. Osseointegrated implants do no present any periodontal ligature and are more firmly anchored to the bone. The difference presented by this type of anchorage has led to some concern about the limited flexibility of the osseointegrated implant to share the functional loads with the connected teeth. This study intended to follow-up prospectively the periodontal parameters bleeding index, probing depth between the pillar tooth of an implant supported prosthesis with one control tooth of the same patient and also the implants that support theses prostheses. That is why subtraction radiography of the region in which the prosthesis was placed was used, with radiographs taken at prosthesis placement, after six months and one year of use to verify if the periimplant osseous support had or had not undergone changes. Twelve patients with normal health conditions were selected who presented a posterior area edentulous jaw where a prosthetic rehabilitation by a fixed prosthesis joining tooth to implant was indicated. Patients were treated with an implant of one stage of 10mm standard Straumann (ITI) with a 2.8 mm polished neck, in which the remaining intraosseous portion of the implant has a treated surface of 4.1 mm diameter. The implant was placed in the space where according to the protocol, the more distal retainer of the future fixed partial prosthesis would be located. Digital radiographs were assessed with a subtraction radiography software Matrox Inspector version eight, to corroborate the change of contrast in the radiographs when superimposed, with values observed in the implant compared with the success criteria , widely mentioned in surveyed studies. All implants placed in patients became osseointegrated. There was no record of bone change around them and in the dental pillars of the prostheses at the one year follow-up. Prostheses continue to be in excellent conditions after the one year follow-up based upon clinical and radiographic analyses. Furthermore, in accordance with the Wilcoxon test of matched pairs and signed rank, it was concluded that there was no statistical difference between each group of each patient during the time period analyzed (baseline and one year) as well as when the pillars were compared to their respective controls.

Nesta pesquisa foi comparada a diferença das medidas obtidas utilizando-se a análise cefalométrica do perfil tegumentar tendo como base a análise facial de Arnett relacionada à Horizontal Verdadeira com a análise cefalométrica do perfil tegumentar feita a partir do Plano de Frankfurt. Utilizamos 140 radiografias cefalométricas requisitadas como parte de documentação ortodôntica, obtidas de pacientes com idade variando de 06 a 49 anos, sendo 64 do sexo masculino e 76 do sexo feminino, pertencentes ao arquivo do IOM - (Instituto de Odontologia Multidisciplinar) ? RJ. As radiografias cefalométricas em norma lateral foram obtidas pelo mesmo operador, obedecendo ao protocolo adotado pelo IOM. Todos os pacientes foram orientados a assumir a Posição Natural da Cabeça, tendo como referência um espelho posicionado a frente e a Linha Vertical Verdadeira foi obtida por meio da utilização de um fio metálico unido à um prumo de chumbo, posicionado próximo à margem anterior do chassi porta-filme, de forma que apareça à frente do perfil tegumentar do paciente. A partir das medidas lineares obtidas nas Análises Cefalométricas dos Tecidos Moles, foram realizadas análises estatísticas visando dois objetivos: comparar as medidas de A à I obtidas nos traçados (um utilizando como referência uma perpendicular ao Plano Horizontal de Frankfurt e o outro à Linha Vertical Verdadeira) e analisar os resultados comparativamente. Após a análise estatística (Kolmogorov-Smirnov, para distribuição normal de dados; t-Student para amostras emparelhadas e teste não paramétrico de Wilcoxon) e a interpretação dos resultados obtidos, concluímos que houve diferenças significantes entre as formas de medidas das variáveis A, B, C, D, F, G e I, pois o valor do nível descritivo (p-valor) se apresentou abaixo de 0,05. Entretanto para as medidas E e H o valor do nível descritivo (p-valor) se apresentou maior que 0,05, demonstrando não haver diferenças significantes entre as formas dessas medidas. As correlações entre as medidas apresentadas estabelecidas pela análise facial de Arnett, de acordo com este estudo, não deverão ser utilizadas em pacientes que se submeteram à radiografias cefalométricas realizadas a partir do Plano Horizontal de Frankfurt, salvo no caso da distância interlabial, representada pela medida H, que além de não apresentar diferenças significantes neste estudo, não tem, segundo a análise de Arnett, correlação com nenhuma outra medida. / In this research a comparison was made between the differences in measurements obtained using the soft tissue profile?s cephalometric analysis based on Arnett?s facial analysis related to the true vertical with the cephalometric analysis of soft tissue profile based on the Frankfurt Plan. A total of 140 lateral cephalometric radiographs were used as part of the orthodontic documentation, taken from patients whose ages ranged from 06 to 49 years of age, of these 64 males and 76 females, being part of the files of the IOM (Instituto de Odontologia Multidisciplinar do Rio de Janeiro). The lateral cephalometric radiographs were obtained from the same operator obeying the protocols adapted by the IOM. All patients were oriented to place themselves in the Natural Head Posture using, as a reference, a mirror in front of then and the true vertical line was obtained using a metal wire and a plumb-line, placed close to the frontal chassis of the film chamber, in such a way that it appears in front of the soft tissue profile of the patient. Parting from the lineal measurements obtained from the Cephalometric Analyses of the Soft Tissues statistical analyses were made relating to two objectives: to compare the measurements from A to I obtained from the drafts/ sketches (one using as it reference a perpendicular to the Frankfurt Horizontal Plane and the other the True Vertical Line), comparatively analyse these results. After the statistical analysis (Kolgomorov Smirnov) for a normal data distribution: t-student for matched pairs and the no-parametric Wilcanox test) and the analysis of the results obtained, it was concluded that there were significant differences between the forms of the measurements of the variables A, B, C, D, F, G and I since the descriptive value (p-value) was below 0,05. The measurements for E and H, however, being over 0,05, showing than there were no significant differences between these forms of measurement. The correlation between the demonstrated measurements established by Arnett?s facial analysis, in accordance with this study, should not be used in patients who have undergone lateral cephalometric radiograph initiated on the basis of the Frankfurt Horizontal Plane except in the case of interlabial distance represented by the measurement H, which even differences in this study, does not have, according to Arnett?s studies, correlations with any other measurements.

O diagnóstico radiográfico é baseado na análise das diferenças das densidades ópticas (DO) do filme, que deveriam ser provocadas apenas pelas estruturas anatômicas do paciente. Entretanto, a intensidade do feixe de raios X não é uniforme devido a um efeito intrínseco do equipamento de aquisição de imagem, conhecido como efeito \"heel\". Estas variações prejudicam tanto a análise visual quanto o processamento computacional (CAD) das pequenas estruturas anatômicas. O presente trabalho apresenta um método computacional que corrige as diferenças de densidades ópticas produzidas na radiografia pelo efeito \"heel\". Esse método foi implementado utilizando ambiente de programação Delphi, rotinas em C e Matlab. O método simula a distribuição da intensidade ao longo do campo de radiação, determinando o caminho de absorção que os fótons sofrem dentro do alvo utilizando os modelos de Kramers e Fritz Livingston. Calcula a correlação espacial entre a radiografia e a imagem simulada, localizando o eixo anodo/catodo e o centro do campo nas duas imagens, empregando a função de correlação estatística de Pratt e a função de mapeamento de Zitová e Flusser. Calcula tanto os percentuais de radiação recebidos para cada ponto simulado em relação à radiação ao centro do campo, quanto os percentuais dos níveis de cinza de cada pixel da radiografia e corrige esse valor em função do correspondente na simulação. O algoritmo desenvolvido permitiu determinar a posição do centro do campo de radiação com precisão em torno de 1% e eliminou aproximadamente 90% do efeito \"heel\" na radiografia permitindo que os objetos apresentassem densidades ópticas coerentes com suas absorções específicas. Um estudo preliminar mostrou que esse método poderá ser utilizado como pré-processamento dos sistemas CAD. / The radiographic diagnosis is based on the analysis of the film optical density differences that should be created only by the patient anatomical structures. However, the intensity of the x-ray beam is not uniform due to an intrinsic effect to the image acquisition equipment, known as heel effect. These variations damage the visual analysis as well the (CAD) computer processing of the small anatomical structures. The current work presents a computer method that corrects the optical densities differences generated in the radiography by heel effect. This method was implemented using Delphi Programming Environment, routines in C and Matlab. The method simulates the intensity distribution along the radiation field, determining the absorption path that photons suffer inside the target using the models of Kramers and Fritz and Livingston. It calculates the space correlation between the radiography and the simulated image, determining the anode/cathode axis and the field center in the two images, using the statistics function of Pratt and the mapping function of Zitová and Flusser. It calculates as much the received radiation, percentage for each simulated point in relation the field center radiation, as the gray scales percentage of each radiography pixel and corrects their values as function of the correspondent in the simulation. The developed algorithm has allowed to determine the center position of the radiation field with about 1% precision and approximately eliminated 90%of the heel effect in the radiography, allowing the objects to present optical densities coherent with their specific absorptions. A preliminary study has showen that this method can be used as preprocessing of CAD systems.

Die chirurgische und strahlentherapeutische Behandlung oropharyngealer Tumoren führt häufig zu einer Beeinträchtigung des Schluckens und Sprechens. Das Ziel dieser Arbeit ist die Untersuchung des Schweregrades der Schluck- und Sprechprobleme bei Patienten, die wegen Tumoren der Regio tonsillaris nach unterschiedlichen Operationsmethoden behandelt wurden. 54 Patienten mit oropharyngealen Tumoren (unterteilt nach den Operationsmethoden: A: Tumortonsillektomie; B: Oropharynxteilresektion mit primärem Wundverschluß; C: Oro-pharynxteilresektion mit plastischer Rekonstruktion) wurden mittels Befragung, mit einem standarisierten Fragebogen, einem kompletten HNO-Status inklusive transnasaler Endo-skopie, mit drei unterschiedlichen Sprachverständlichkeitstests und einer Röntgenkine-matographie untersucht. Die besten funktionellen Resultate (sowohl der Schluck- als auch der Sprechfunktion) zeigten sich in Gruppe A, während sich in den Gruppen B und C deutlich schlechtere Ergebnisse fanden. Zwischen den Gruppen B und C ließen sich nur geringe Unterschiede feststellen. Die statistische Analyse konnte eine positive Korrelation der Ergebnisse innerhalb der Sprach-verständlichkeitstests sowie der drei Tests untereinander nachweisen. Die Arbeit zeigt, daß durch Oropharynxteilresektionen mit primärem Wundverschluß und mit plastischer Rekonstruktion annähernd gleichwertige Resultate erzielt werden, obwohl der operationsbedingte Gewebedefekt vor plastischer Rekonstruktion deutlich größer ist. Diese Ergebnisse widersprechen einigen Literaturangaben, die schlechtere funktionelle Ergebnisse nach plastischer Rekonstruktion beschreiben. Die Arbeit zeigt außerdem, daß sich die drei verwendeten Sprachverständlichkeitstests für die Untersuchung der beeinträchtigten Sprech-funktion nach operativer Behandlung oropharyngealer Tumoren eignen. / The surgical and radiotherapeutical treatment of oropharyngeal tumors often results in swallowing and speech malfunction. The purpose of this study is to investigate the severity of swallowing and speech malfunction in patients with tumors of the tonsillar region, which were treated by different surgical strategies. 54 Patients with oropharyngeal tumors (seperated according to the surgical strategy: A: radical tonsillectomy; B: partial oropharyngectomy and primary closure; C: partial oropharyngectomy and plastic reconstruction) were investigated by interrogation, a standardized questionaire, a full otorhinolaryngological examination including transnasal endoscopy, three different speech tests and a radiographic swallow examination. The best functional results (regarding swallow- as well as speech function) were found in group A. The functional results in group B and C were distinctly worse, but only minimal differences could be found between these two groups. Statistical analysis confirmed a positive correlation of the results of the three speech tests and beetween the three speech tests. The study shows very similar functional results after partial oropharyngectomy with primary closure and partial oropharyngectomy with plastic reconstruction, although the tissue defect before plastic reconstruction was distinctly greater. These results differ from some results in the literature, which describe worse functional results after plastic reconstruction. The study also shows the usability of the three speech tests to assess variant degrees of speech malfunction after surgical and radiotherapeutical treatment of oropharyngeal tumors.