A mamografia é um método de diagnóstico por imagem que utiliza radiação X. No controle de qualidade dos mamógrafos, as câmaras de ionização são usadas para verificar se os parâmetros de exposição das pacientes estão corretos. Contudo, as câmaras de ionização comerciais para dosimetria em mamografia representam alto custo para clínicas de pequeno e médio porte que desejam ter esse equipamento ou para profissionais que trabalham com controle de qualidade. Assim, a característica inovadora deste trabalho foi desenvolver câmaras de ionização para este fim. Neste trabalho foram projetadas, construídas e caracterizadas câmaras de ionização para feixes de radiação X, no intervalo de energia de mamografia. As câmaras de ionização foram caracterizadas em feixes padronizados de radiação X no LCI/IPEN. Os testes principais de caracterização das câmaras de ionização foram: curva de saturação, linearidade da resposta, dependência energética e angular. Os testes de estabilidade da resposta das câmaras de ionização também foram realizados, apresentando resposta dentro de 2,0 % para estabilidade em longo prazo. Os resultados dos demais testes foram em conformidade com normas internacionais. Essas câmaras de ionização foram ainda submetidas a testes de controle de qualidade de mamógrafos quanto à linearidade das taxas de kerma no ar, à determinação das camadas semirredutoras e das doses glandulares médias. Para a linearidade da taxa de kerma, os valores obtidos foram abaixo dos 10 %, como estabelecido em norma. A dose glandular determinada com as câmaras desenvolvidas apresentaram valores comparáveis com os da câmara de referência testada, com variação prevista em recomendações internacionais. / Mammography is an imaging method that uses X-rays. The use of ionization chambers in mammography quality control programs presents an essential role which is to verify whether the parameters of the patient exposure are correct. However, the commercial ionization chambers for dosimetry in mammography represent a high cost for small and medium size clinics that wish to have this equipment or for professionals that work with quality control programs. The innovative feature of this work was to develop ionization chambers for this purpose. In this work ionization chambers for X radiation beams in the mammography energy range were designed, constructed and characterized. The ionization chambers were tested in standard X radiation beams at the LCI/IPEN. The main characterization tests performed with the ionization chambers were: saturation curve, linearity of response, angular and energy dependence. The response stability tests of the ionization chambers were also conducted at the LCI, presenting results within 2.0 % for long-term stability. The results of the remaining tests are in accordance with international standards. These ionization chambers were also submitted to quality control tests of mammography equipment: linearity of the air kerma rates, determination of half-value layers and mean glandular doses. The results for air kerma rate linearity were less than 10 %, as recommended in international standards. The mean glandular dose obtained with the developed chambers presented values comparable to those of commercial ionization chambers tested, with an estimated variation within international standards.

Este trabalho tem por objetivo a investigação do comportamento de equipamentos de radiodiagnóstico em termos da qualidade da imagem produzida e a subseqüente aplicação desses resultados na otimização do desempenho de esquemas computacionais de auxílio ao diagnóstico, também conhecidos como esquemas CAD (do inglês, Computer-Aided Diagnosis). A principal meta consiste no desenvolvimento de técnicas de pré-processamento para imagens mamográficas digitalizadas que as realçasse de acordo com as características e limitações dos equipamentos utilizados na sua aquisição. A proposta está dividida em duas etapas. Na primeira, foram determinadas as características relativas tanto à resolução espacial como à resolução de contraste de diversos equipamentos mamográficos, avaliadas respectivamente pelas funções de transferência óptica e espectros de Wiener do ruído. Isto permitiu, numa segunda etapa, o desenvolvimento de um filtro digital específico para o pré-processamento de diferentes conjuntos de mamogramas digitais, separados de acordo com os equipamentos utilizados no processo de aquisição. Dessa forma, cada imagem mamográfica teve sua qualidade melhorada de acordo com as características do equipamento que a gerou, determinadas na primeira etapa. Essas imagens, depois de realçadas, foram utilizadas em um esquema CAD previamente desenvolvido, onde pôde ser observada uma melhora em até 12% no seu desempenho quando comparado aos resultados obtidos com imagens mamográficas não realçadas. / The purpose of this work is to evaluate the quality of radiological equipment and their images in order to use these evaluations to improve the performance of a computer-aided diagnosis (CAD) scheme. The mean idea is about the development of image processing techniques to enhance digital mammograms according to the characteristics of the X-ray unit used for image acquisition. This work is basically divided in two parts. In the first one, it were determined the characteristics related to spatial and contrast resolution of several mammographic equipment, evaluated respectively from the optical transfer function and noise Wiener spectrum. This evaluation allowed, in a second part, the development of a preprocessing technique to enhance different set of digital mammographic images, gathered according to the equipment used on its acquisition process. Thus, each mammographic image had its quality improved in conformity with the characteristics of the equipment used on its acquisition, determined in the first part of this work. These images, after the enhancement process, were used on a previously developed CAD scheme. It was observed an improvement of 12% on the CAD performance using pre-processed mammograms compared to the results obtained when using non-enhanced mammographic images.

Este trabalho apresenta a proposta de uma metodologia para classificação de nódulos mamários por contorno. O contorno do nódulo apresenta difícil interpretação pelos especialistas, devido à dificuldade de vizibilização e o baixo contraste das imagens mamográficas. As imagens utilizadas foram obtidas do banco de imagens mamograficas do LAPIMO, no total foram utilizadas 135 imagens contendo laudos por contorno. Através das imagens mamográficas digitalizadas são recortadas região de interesse (RI) de onde serão extraídos descritores de textura, intensidade e geométricos com o objetivo de caracterizar os padrões de contorno de nódulos. Após a extração desses descritores foram utilizados dois métodos de seleção de atributos, um utilizando rede neural self-organizing map (SOM) e Gaussianas e outro utilizando matriz de covariância. Os atributos extraídos serviram de entrada para duas redes neurais a multi-layer perceptron (MLP) e SOM, através do qual, foram realizados diversos treinamentos utilizando diferentes entradas, várias topologias e diferentes saídas, devido às várias combinações de classes. Dentre todos os treinamentos realizados, o treinamento escolhido para compor o classificador final foi o conjunto formado pelas 5 classes, obtido pela rede neural MLP com topologia de 20 neurônios de entrada, 40 neurônios na primeira camada intermediária, 20 neurônios na segunda cama intermediária e 5 neurônios na camada de saída, com taxa de aprendizagem igual a 0,9 e erro menor que 0,01, as 20 entradas foram selecionadas através da rede SOM e Gaussianas. O acerto obtido utilizando 135 RIs e pesos fixos foi de 89% de acerto total, Az igual a 0,98, falso negativo igual a 5% e falso positivo igual a 7%. O classificador apresentado nesse trabalho será acrescentado ao classificador já existente no esquema CAD em mamografia. / This work presents the proposal of a methodology for mammary nodules classification by their contour. The nodule bounder is had to interpret due to the low contrast of the mammographic images. Images used in the test obtained from the LAPIMO’s database a 135 of images, with information about the masses. From regions of interest (RÓIS) selected in such images texture, intensity and geometric features were extracted in order to characterize the patterns of nodules contour. After the features extraction two methods of features selection, were used: one using self-organizing map (SOM) neural networks together Gaussian distributions analysis and another using covariance matrix. The extracted features were the input for two neural networks, a multi-layer perceptron (MLP) and a SOM. Several trainings were accomplished using different inputs, several topologies and different exits, regarding several classes combinations. Among all of the trainings, the choice has corresponded to the group formed by 5 classes, obtained for the MLP neural networks in a topology of 20 input neurons, 40 neurons in the first intermediate layer, 20 neurons in the second intermediate layer and 5 neurons in the exit layer, with learning rate of 0.9 and error smaller than 0.01. The 20 inputs were selected by the SOM network together Gaussian distributions. The performance using 135 ROIs and fixed weights has registred 89% of right responses with Az = 0.98, false negative rate of 5% and false positive rate of 7%. The classifier presented in this work is being implemented in the general classifier as part of our group CAD scheme in mammography.

Submitted by Rosina Valeria Lanzellotti Mattiussi Teixeira (rosina.teixeira@unisantos.br) on 2016-02-20T13:58:02Z No. of bitstreams: 1 Katucha Rocha de Almeida.pdf: 1145204 bytes, checksum: 8da70f49b690eb6b7404c3f5f0a86b27 (MD5) / Made available in DSpace on 2016-02-20T13:58:02Z (GMT). No. of bitstreams: 1 Katucha Rocha de Almeida.pdf: 1145204 bytes, checksum: 8da70f49b690eb6b7404c3f5f0a86b27 (MD5) Previous issue date: 2015-12-10 / Introduction: Breast cancer is the most common type of cancer among women, in both developing and developed countries, represented by 25% of all types of diagnosed cancer. Mammography screening for breast cancer is a public health strategy in situations with high incidence numbers and mortality from cancer, as observed in Brazil. Objective: To analyze the performance of mammography screening in Praia Grande city female residents. Methods: A public survey in Praia Grande city, in the state of São Paulo. For the study on undergoing mammography screening exam among 50- to 69 year-old women, according to mammographic screening recommendations, a subsample of 257 women was used, with a non response rate of 0%. Results: Among the 50 to 69 female age-group (257), 70 (27%) underwent mammography screening in the 12 months prior to the survey, more than half (60%) used the public sector service. In the multivariate analysis, breast ultrasound was positively associated with mammography in the last 12 months. Conclusion: Women with recommended ages for tracking the Grand Beach County have low achievement of mammography. The awareness through implementation of public policies on the importance of this examination within what is recommended, to reduce the mortality from the disease, which is a leading cause of death among women in Brazil and worldwide. / Introdução: O câncer de mama é o tipo mais prevalente entre as mulheres, tanto em países em desenvolvimento quanto em países desenvolvidos, representado por 25% de todos os tipos de câncer diagnosticados. O exame de mamografia como rastreamento para o câncer de mama é uma estratégia de saúde pública em situações onde há elevados números de incidência e mortalidade pela neoplasia, como observado no Brasil. Objetivo: Analisar a realização do exame de mamografia em mulheres residentes do Município de Praia Grande. Métodos: Inquérito populacional no Município de Praia Grande, Estado de São Paulo. Para o estudo sobre realização do exame de mamografia entre mulheres de 50 a 69 anos, referente ao preconizado para realização de rastreamento mamográfico, foi utilizada para análise uma subamostra de 257 mulheres, com taxa de não respostas de 0%. Resultados: Das mulheres na faixa etária dos 50 aos 69 anos (257), 70 (27%) realizaram o exame de mamografia nos últimos doze meses que antecederam a pesquisa, sendo mais da metade (60%) pelo setor público. Na análise múltipla, manteve-se associada positivamente apenas a realização do ultrassom de mamas nos últimos doze meses. Conclusão: Mulheres com idades preconizadas para rastreamento do Município de Praia Grande apresentam baixa realização do exame mamográfico. A conscientização por meio de implementação de políticas públicas sobre a importância da realização deste exame dentro do que é preconizado, visa diminuir a mortalidade pela doença, que é uma das principais causas de morte entre as mulheres no Brasil e no mundo. Descritores: Mamografia; Rastreamento; Câncer

Contexte: La mammographie est une modalité d’imagerie médicale à faible dose permettant la détection du cancer mammaire à un stade précoce. Lors de l'examen, le sein est comprimé entre deux plaques afin d'uniformiser son épaisseur et d'étaler les tissus. Cette compression améliore la qualité clinique de l'examen mais elle est également source d'inconfort chez les patientes. Bien que la mammographie soit la méthode de dépistage la plus efficace du cancer du sein, l’inconfort ressenti peut dissuader les femmes de passer cet examen. Par conséquent, une technique alternative de compression du sein prenant en compte le confort de la patiente, en plus de l’amélioration de la qualité d'image, présente un grand intérêt.Méthodes: Dans ce travail, nous avons proposé un nouvel environnement de simulation permettant l'évaluation de différentes techniques de compression du sein. La qualité de la compression a été caractérisée en termes de confort de la patiente, de la qualité d'image et de la dose glandulaire moyenne délivrée. Afin d'évaluer la déformation du sein lors de la compression, un modèle biomécanique par éléments finis du sein a été développé. Ce dernier a été calibré et évalué en utilisant des volumes IRM d'une volontaire dans trois configurations différentes (sur le dos, le ventre et de côté). Par ailleurs, la qualité d'image a été évaluée en utilisant un environnement de simulation d'imagerie auparavant validé pour la simulation de l'acquisition d'images en mammographie.Résultats: La capacité de notre modèle biomécanique à reproduire les déformations réelles des tissus a été évaluée. Tout d'abord, la géométrie du sein dans les trois configurations a été estimée en utilisant des matériaux Néo-Hookeens pour la modélisation des tissus mous. Les propriétés mécaniques des différents constituants du sein ont été estimés afin que les géométries du sein dans les positions couchée sur le ventre et couchée soient le plus proches possibles des mesures. La distance de Hausdorff entre les données estimées et les données mesurées est égale à 2.17 mm en position couché sur le ventre et 1.72 mm en position couché sur le dos. Le modèle a ensuite été évalué dans une troisième configuration sur le côté, avec une distance de Hausdorff étant alors égale à 6.14 mm. Cependant, nous avons été montré que le modèle Néo-Hookeen ne peut pas décrire intégralement le comportement mécanique riche des tissus mous. Par conséquent, nous avons introduit d'autres modèles de matériaux basés sur la fonction d'énergie de Gent. Cette dernière hypothèse a permis de réduire l'erreur maximale dans la configuration couchée sur le ventre et dos incliné d’environ 10 mm.Le couplage entre la simulation de la mécanique du sein et la simulation d'aquisition d'image nous ont permis d'effectuer deux études préliminaires. Dans la première étude, les différences entre les pelotes de compression standard rigide et flex ont été évaluées. Selon les simulations effectuées, l'utilisation de la pelote flex pour la compression du sein a le potentiel d'améliorer le confort de la patiente sans affecter la qualité de l'image ou la dose glandulaire moyenne.Dans la seconde étude, l'impact du positionnement du sein sur la mécanique globale de la compression mammaire a été étudié. Nos simulations confirment que rapprocher la pelote de compression de la cage thoracique peut augmenter l'inconfort de la patiente. Selon les données estimées, pour une même épaisseur du sein sous compression, la force appliqée au sein peut être s'accroitre de 150%.Conclusion: L'estimation réaliste de la géométrie du sein pour différentes configurations sous l'effet de la gravité, ainsi que les résultats conformes aux descriptions cliniques sur la compression du sein, ont confirmé l'interêt d'un environnement de simulation dans le cadre de nos études. / Background: Mammography is a specific type of breast imaging that uses low-dose X-rays to detect breast cancer at early stage. During the exam, the women breast is compressed between two plates in order to even out the breast thickness and to spread out the soft tissues. This compression improves the exam quality but can also be a source of discomfort. Though mammography is the most effective breast cancer screening method, the discomfort perceived during the exam might deter women from getting the test. Therefore, an alternative breast compression technique considering the patient comfort in addition to an improved clinical image quality is of large interest.Methods: In this work, a simulation environment allowing the evaluation of different breast compression techniques was put forward. The compression quality was characterized in terms of patient comfort, image quality and average glandular dose. To estimate the breast deformation under compression, a subject-specific finite element biomechanical model was developed. The model was calibrated and evaluated using MR images in three different breast configurations (supine, prone and supine tilted). On the other hand, image quality was assessed by using an already validated simulation framework. This framework was largely used to mimic image acquisitions in mammography.Findings: The capability of our breast biomechanical model to reproduce the real breast deformations was evaluated. To this end, the geometry estimates of the three breast configurations were computed using Neo-Hookean material models. The subject specific mechanical properties of each breast's structures were assessed, such as the best estimates of the supine and prone configurations were obtained. The Hausdorff distances between the estimated and the measured geometries were equal to 2.17 mm and 1.72 mm respectively. Then, the model was evaluated using a supine tilted configuration; with a Hausdorff distance of 6.14 mm was obtained in that case. However, we have showed that the Neo-Hookean strain energy function cannot totally describe the rich mechanical behavior of breast soft tissues. Therefore, alternative material models based on the Gent strain energy function were proposed. The latter assumption reduced the maximal error in supine tilted breast configuration by about 10 mm.The coupling between the simulations of the breast mechanics and the X-ray simulations allowed us to run two preliminary studies. In the first study, the differences between standard rigid and flex compression paddles were assessed. According to the performed simulations, using the flex paddle for breast compression may improve the patient comfort without affecting the image quality and the delivered average glandular dose.In the second study, the impact of breast positioning on the general compression mechanics was described. Our simulations confirm that positioning the paddle closer to the chest wall is suspected to increase the patient discomfort. Indeed, based on the estimated data, for the same breast thickness under compression, the force applied to the breast may increase by 150%.Conclusion: The good results we get for the estimation of breast deformation under gravity, as well as the conforming results on breast compression quality with the already published clinical statements, have shown the feasibility of such studies by the means of a simulation framework.

While sisters of breast cancer patients are at increased risk for developing breast cancer due to their family cancer history and age, little research with first-degree relatives of cancer patients has focused solely on sisters. To address this issue, the current study examined sisters screening and health behaviors and the predictors of these behaviors. In accordance with the Parallel Processing Theory, the current study assessed the relationship of cognitive and emotional factors to screening and health-promoting behaviors among sisters of breast cancer patients. In addition, this study expanded upon the Parallel Processing Theory by also examining the relationship of interpersonal factors to screening and health-promoting behaviors. One-hundred-twenty sisters of breast cancer patients from 89 different families completed questionnaires assessing perceived risk of breast cancer, perceived response efficacy of mammography, diet, and exercise, breast cancer worry, trait anxiety, involvement in sister's cancer care, satisfaction with the sister relationship, mammography screenings, physical activity, and amount of fruits and vegetables consumed. Findings indicated that cognitive, emotional, and relational factors were significantly related to mammography screenings, but not to diet or exercise. Specifically, response efficacy for mammography screening was positively related to mammography screening; while trait anxiety and involvement in sister's care were negatively related to mammography screening. Additional analyses indicated that breast cancer worry had a curvilinear relationship with mammography screenings, such that no relationship was seen for women with lower breast cancer worry; for women with higher levels of worry, the greater their worry, the less likely they were to obtain mammography screenings. Breast cancer worry was also found to interact with involvement in care, such that among women less involved in their sister's care, greater breast cancer worry was associated with having fewer mammography screenings. However, for women more involved in their sister's care, greater breast cancer worry was associated with having more mammography screenings. Future research should further assess whether a teachable moment exists related to the family member's cancer diagnosis and treatment during which to encourage the FDR to engage in screening health-promoting behaviors.

Breast cancer is a widespread public health issue in the United States which affects all women. Although mammography is a proven screening tool, screening rates vary widely. Self-reported health status may play a role in how women perceive their risks for developing breast cancer, which may affect mammography use. The purpose of this cross-sectional survey study was to assess the association between self-reported health status and perceived risk for developing breast cancer, as well as perceived barriers towards mammography screening and use. Social action theory, which holds that social and the psychological factors influence health behaviors, served as the theoretical foundation of the study. A convenience sample of 309 African American, non-Hispanic White, and Hispanic women, aged 30+, was recruited to participate in the study. Linear and logistic regression analyses revealed the model including all variables were significance between self-reported health status, demographic characteristics, and the dependent variables perceived risk of breast cancer, receipt of a mammogram in the last 2 years, and barriers (personal, economic, and health). However, self-reported health status was not a significant individual predictor in any of the analyses, and the null hypotheses for the research questions were not rejected. This study may promote positive social change by providing information on the necessity of interdisciplinary and interrelated educational and intervention approaches to address the challenges of women from diverse populations receiving regular mammograms.

Breast cancer is the second leading cause of cancer death among women in the United States. Nonadherence to recommended screening guidelines and lack of screening contribute to late stage diagnosis and increased morbidity and mortality among racial and ethnic women in the United States. The purpose of this study was to assess breast cancer screening practices, knowledge, and beliefs among Cameroonian immigrant women who were 40 years and older living in the metropolitan Washington, D.C. region. This quantitative cross-sectional study was guided by the health belief model and used the revised version of Champion's health belief model scale. A convenience sample (N=267) responded to a 60-item self-administered online survey that assessed knowledge of breast cancer screening, demographic variables, constructs of the health belief model and adherence (defined as obtaining a mammogram within two years). Data analyses performed included descriptive analysis, correlational and multiple linear regression. Results of this study revealed that increased level of education and self-efficacy were associated with greater knowledge of the benefits of mammography. Additionally, women who had more self-efficacy in obtaining a mammogram, perceived less cultural barriers, lived longer in the United States, and who had a regular healthcare provider were more likely to be adherent. Study findings suggest that positive social change can be achieved by empowering women to take control of their health. Efforts promoting awareness of breast cancer screening guidelines and facilitating access to a regular healthcare provider could significantly increase uptake of screening services and lead to better health outcomes and reduced mortality.

Early detection, diagnosis, and suitable treatment are known to significantly improve the chance of survival for breast cancer (BC) patients. To date, the most cost effective method for screening and early detection is screen-film mammography, which is also the only tool that has demonstrated its ability to reduce BC mortality. Full-field digital mammography (FFDM) is an extension of screen-film mammography that eliminates the need for film-processing because the images are detected electronically from their inception. Tomosynthesis is an emerging technology in digital mammography built on the FFDM framework, which offers an alternative to conventional two-dimensional mammography. Tomosynthesis produces three-dimensional (volumetric) images of the breast that may be superior to planar imaging due to improved visualization. In this work preliminary tomosynthesis data derived from cadaver breasts are analyzed, which includes volume data acquired from various reconstruction techniques as well as the planar projection data. The noise and power spectra characteristics analyses are the focus of this study. Understanding the noise characteristics is significant in the study of radiological images and in the evaluation of the imaging system, so that its degrading effect on the image can be minimized, if possible and lead to better diagnosis and optimal computer aided diagnosis schemes. Likewise, the power spectra behavior of the data are analyzed, so that statistical methods developed for digitized film images or FFDM images may be applied directly or modified accordingly for tomosynthesis applications. The work shows that, in general, the power spectra for three of the reconstruction techniques are very similar to the spectra of planar FFDM data as well as digitized film; projection data analysis follows the same trend. To a good approximation the Fourier power spectra obey an inverse power law, which indicates a degree of self-similarity. The noise analysis indicates that the noise and signal are dependent and the dependency is a function of the reconstruction technique. New approaches for the analysis of signal dependent noise were developed specifically for this work based on both the linear wavelet expansion and on nonlinear order statistics. These methods were tested on simulated data that closely follow the statistics of mammograms prior to the real-data applications. The noise analysis methods are general and have applications beyond mammography.

Abstract One of every eight women in the United States will be diagnosed with breast cancer in her lifetime. Although early detection of breast cancer is the most effective method of assuring survival, many women throughout the country do not avail themselves of this advantage. This study examined mammography screening practices of women age 55 and older who attended senior citizen centers in rural, non-metro, and metro counties in the areas designated by the Tennessee Department of Health as the Eastern Grand Division of Tennessee. Data was collected from four hundred women from fourteen counties in East Tennessee using the Champion Health Belief Survey instrument. Data analysis was done using SPSS software. Descriptive analyses were presented consisting of the percentage or mean responses for each of the survey items. Chi Square and ANOVA were used to test whether the observed proportions for mammography screening differed from the hypothesized proportions. Results from this study revealed that health beliefs and demographic characteristics were associated with a higher likelihood of having recent mammography. The health beliefs of participants concerning the perceived benefits to mammograms and the perceived barriers to obtaining mammograms significantly impact one’s willingness to engage in breast cancer screening practices. Also, the woman’s perceived susceptibility to the disease of breast cancer and their perceived seriousness of the disease of breast cancer have a significant impact on breast cancer screening practices. Additionally, a significant difference was found in the screening practices of women based on whether they had health insurance and if their physician recommended a mammogram.