Objectives: Ductal carcinoma in situ (DCIS) is a non-invasive lesion of an increasing clinical importance. Individual risk assessment is essential for an optimal treatment. Our objective was to identify clinical and molecular characteristics of a subgroup of DCIS with an unfavorable prognosis. Methods: In a population study, we analyzed women with DCIS diagnosed within one mammography screening unit. In the experimental part of this work, we conducted a comparative analysis of five biological markers in normal tissue, DCIS and invasive breast cancer by means of gene expression analysis and analysis of loss of heterozygosity (LOH). Results: We demonstrated a high proportion of pure (no invasive component) DCIS (14.41%) of all breast lesions described as malignant. In our sample, we saw a homogeneous distribution of risk factors without noting a clear pattern identifying high-risk subtypes. We noted significant differences in clinical management of tumors with similar characteristics, which demonstrates the present state of limited use of clinical predictors. In the laboratory experiment, we showed differences in loss of heterozygosity (LOH) between DCIS and invasive breast cancer for BRCA1 (8.69% vs. 44.74%) and BRCA2 (9.52% vs. 45.0%). In contrast, we did not find any differences for p53 (31.82%...

Mammography is used to aid early detection and diagnosis systems. It takes an x-ray image of the breast and can provide a second opinion for radiologists. The earlier detection is made, the better treatment works. Digital mammograms are dealt with by Computer Aided Diagnosis (CAD) systems that can detect and analyze abnormalities in a mammogram. The purpose of this study is to investigate how to categories cropped regions of interest (ROI) from digital mammogram images into two classes; normal and abnormal regions (which contain microcalcifications). The work proposed in this thesis is divided into three stages to provide a concept system for classification between normal and abnormal cases. The first stage is the Segmentation Process, which applies thresholding filters to separate the abnormal objects (foreground) from the breast tissue (background). Moreover, this study has been carried out on mammogram images and mainly on cropped ROI images from different sizes that represent individual microcalcification and ROI that represent a cluster of microcalcifications. The second stage in this thesis is feature extraction. This stage makes use of the segmented ROI images to extract characteristic features that would help in identifying regions of interest. The wavelet transform has been utilized for this process as it provides a variety of features that could be examined in future studies. The third and final stage is classification, where machine learning is applied to be able to distinguish between normal ROI images and ROI images that may contain microcalcifications. The result indicated was that by combining wavelet transform and SVM we can distinguish between regions with normal breast tissue and regions that include microcalcifications.

This dissertation focuses on women’s participation in mammography screening, which is a vital component of early detection and effective management of breast cancer. All Swedish women in the age group of 40-74 receive an invitation by mail at regular intervals of 18-24 months. However, about 20% of Swedish women fail to attend the mammography screening they were offered. The impact on mortality within a population is contingent on theparticipation rate, underscoring the importance of making efforts to attain a high level of participation. This thesis is an attemt to improve understanding and awareness of the women’s choices and actions that can influence life or death, especially considering that being a woman is the most significant risk factor for breast cancer. The overall aim of this thesis was to explore the phenomenon of women’s participation in mammography screening by exploring the reasons why women refrain from mammography screening from the perspective of non-attending women (Paper I) and factors that affect women’s participation in mammography screening in the Nordic countries. The research was conducted through qualitative and mixed studies review method studies. The data collection methods comprised ten personal interviews (Paper I), and 16 articles (Paper II). Qualitative content analysis was used to analyse the interviews in an indictive approach (Paper I). A deductive approach with segregated mixed research synthesis was used to analyse and summarise findings from articles in systematic review (Paper II). Health Promotion Model by N. Pender was used as a theoretical framework. Participation in mammography screening is a complex phenomenon that has many dimensions. The thesis results underscore the significance of comprehending the unique and subjective encounters of women in the context of mammography screening. These experiences hold substantial sway over their perspectives and actions regarding this procedure. Additionally, the research suggests that effective communication and prior experiences, whether positive or negative, play pivotal roles in shaping women's knowledge and attitudes towards mammography. These findings align with the biopsychosocial perspective, which underscores the intricate interplay of biological, psychological, and social factors in individuals' lives. Mammography screening, as demonstrated in Paper I, operates as a standardized system aimed at addressing the diverse and individual needs of women. Various factors, such as individual characteristics, past experiences, cognitive factors related to behavior, emotional aspects, competing priorities, and the organizational aspects of screening, collectively influence women's participation in both positive and negative ways (Paper II). Promotional efforts are essential to motivate women to actively engage in their healthcare.

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Breast cancer is the most common cancer type in the United Kingdom. Many women with breast cancer do not show any noticeable symptoms in their early stages, hence regular breast screening is important. In this research focus is on medical imaging and its role in breast cancer screening, diagnosis, and treatment monitoring. Around 10% of all cancers are caused by inherited gene mutations which may cause cancer to run in families. Though, majority of cancer cases (up to 90%) are caused by acquired gene mutations which may also appear to run in families when family members share a particular environment or exposure. Genetic testing is conducted in this research on a number of participants to investigate the cancer cases found among their families. The findings of this research show that significant improvements have taken place in the emergence of hybrid imaging modalities used for breast imaging, through the fusion of different imaging techniques. The findings also provide evidence that similar to cancers caused by inherited gene mutations, cancers caused by non-inherited gene mutations may also appear to run in families when family members share certain environments and exposures or lifestyle behaviours. As a result, a new genetic concept of cancer essential to understand and control the disease is presented in this work which links between the human population origins and migrations, environmental factors and gene mutations, and the development of cancer. Furthermore, a number of cancer prevention strategies are recommended in this study to prevent people from getting the disease.

No description available.

Abstrakt    Bakgrund: Bröstcancer är en av de vanligaste cancerformerna hos kvinnor runt om i världen och utgör en betydande risk för hälsan. För utrikesfödda kvinnor finns särskilda utmaningar när det gäller att gå på mammografiscreening, vilket kan ha allvarliga konsekvenser för deras hälsa. För att säkerställa att alla kvinnor får likvärdig vård och att fler deltar i screeningen är det viktigt att identifiera och lösa dessa hinder. Röntgensjuksköterskor spelar en viktig roll genom att ge stöd, information och skapa en trygg miljö för patienter under mammografiscreening. Genom att förstå och hantera de hinder som utrikesfödda kvinnor möter kan vi sträva mot ett mer inkluderande och effektivt vårdsystem.   Syfte: Syftet med denna studie är att undersöka vilka hinder som utrikesfödda kvinnor möter när det gället att delta i mammografiscreening.  Metod: Studien genomfördes med en kvalitativ metod litteraturöversikt enligt Fribergs metod, där nio artiklar valdes ut för analys och granskning. Sökningen utfördes genom PubMed och Cinahl via Umeå Universitets bibliotekstjänst.  Resultat: Resultaten visade på flera hinder som hindrade utrikesfödda kvinnor från att delta i mammografiscreening. Dessa hinder kategoriserades i tre övergripande huvudkategorier och tio underkategorier: Strukturella hinder, Sociokulturella hinder och Emotionella hinder. Underkategorierna inkluderade bland annat språkbarriärer, bristande kunskap om sjukdomen och screeningen, ekonomiska begränsningar, transportsvårigheter, fatalism, skam och rädsla för smärta.  Konklusion: Sammanfattningsvis visar denna litteraturstudie att utrikesfödda kvinnor möter flera hinder när det gäller att delta i mammografiscreening. För att öka deltagandet är det viktigt att erbjuda anpassad information och stöd samt skapa en trygg och respektfull vårdmiljö. Genom att hantera dessa hinder kan hälso- och sjukvården främja jämlik tillgång till och deltagande i screeningen, vilket är avgörande för tidig upptäckt och behandling av bröstcancer. / Abstract  Background: Breast cancer is one of the most common forms of cancer affecting women worldwide, posing a significant health risk. Immigrant women face specific challenges when it comes to attending mammography screening, which can have serious consequences for their health. To ensure equitable care for all women and increase participation in screening, it is essential to identify and address these barriers. Radiographers play a crucial role by providing support, information, and creating a safe environment for patients during mammography screening. By understanding and addressing the obstacles faced by foreign-born women, we can strive towards a more inclusive and effective healthcare system.  Aim: The aim of this study was to investigate the experiences of immigrant women regarding barriers to participating in mammography screening.   Methods: The study was conducted using a qualitative method of literature review following Friberg's methodology, where nine articles were selected for analysis and review. The search was performed through PubMed and Cinahl via Umeå University's library service.  Results: The results revealed several barriers hindering immigrant women from participating in mammography screening. These barriers were categorized into three overarching main categories and ten subcategories: Structural barriers, Sociocultural barriers, and Emotional barriers. Subcategories included language barriers, lack of knowledge about the disease and screening, economic constraints, transportation difficulties, fatalism, shame, and fear of pain.  Conclusion: In summary, this literature review highlights that immigrant women encounter multiple barriers to participating in mammography screening. To increase participation, it is crucial to provide tailored information and support and create a safe and respectful healthcare environment. By addressing these barriers, healthcare providers can promote equitable access to and participation in screening, which is essential for the early detection and treatment of breast cancer.

The proposed master's thesis investigates the adaptability and efficacy of self-supervised representation learning (SSL) in medical image analysis, focusing on Mammographic Imaging to develop robust representation learning models. This research will build upon existing studies in Mammographic Imaging that have utilized contrastive learning and knowledge distillation-based self-supervised methods, focusing on SimCLR (Chen et al 2020) and SimSiam (Chen et al 2020) and evaluate approaches to increase the classification performance in a transfer learning setting. The thesis will critically evaluate and integrate recent advancements in these SSL paradigms (Chhipa 2023, chapter 2), and incorporating additional SSL approaches. The core objective is to enhance robust generalization and label efficiency in medical imaging analysis, contributing to the broader field of AI-driven diagnostic methodologies. The proposed master's thesis will not only extend the current understanding of SSL in medical imaging but also aims to provide actionable insights that could be instrumental in enhancing breast cancer detection methodologies, thereby contributing significantly to the field of medical imaging and cancer research.

Objectifs : L’objectif a été de d’optimiser les protocoles d’acquisition des examens d’angiomammographie double-énergie, d’étudier la faisabilité de l’angiotomosynthèse pour la détection et la caractérisation des tumeurs mammaires, et d’étudier la faisabilité des biopsies stéréotaxiques sous guidage de l’angiomammographie. Méthodes : Une étude d’optimisation des paramètres d’acquisition de l’angiomammographie a été réalisée dans 4 situations cliniques pour lesquelles la qualité diagnostique requise des images de basse énergie et la dose totale délivrée à la patiente ne sont pas identiques. L’optimisation des paramètres d'exposition (anode/filtre, kVp, mAs) des images de basse énergie (BE) et haute énergie (HE) a été réalisée à partir d’une modélisation théorique de la chaîne d’acquisition. Une validation a été effectuée par mesures expérimentales sur des images de fantôme d’inserts d’iode. Nous avons ensuite étudié la technique d’angiotomosynthèse mammaire basée sur une approche double-énergie. Un nouveau fantôme anthropomorphique numérique du sein et de ses lésions, basé sur l’utilisation de primitives géométriques complexes et d’une technique de maillage surfacique, a été amélioré et utilisé pour évaluer les performances de l’angiomammographie optimisée, puis de l’angiotomosynthèse en comparaison à l’angiomammographie. Enfin, nous avons proposé un scénario pour la réalisation d’un examen de stéréotaxie avec injection d’un agent de contraste iodé et étudié la faisabilité de recombinaison d’image de haute et de basse énergie acquises à des temps différents de l’injection.Résultats et conclusion : Les optima des paramètres d’exposition trouvés par simulation avec les valeurs de SDNRpixel et SDNR2pixel /Dosetotale qui en résultent, ont été confirmés expérimentalement. Les valeurs de SDNR par pixel dans les images recombinées sont augmentées pour toutes les indications cliniques en comparaison à celle obtenues avec SenoBright ® (produit commercial de référence). L'impact sur la qualité de l’image de BE, évalué par des expérimentations sur fantôme CDMAM, a montré que les paramètres optimisés fournissent une détection similaire ou acceptable par rapport à la mammographie standard, à l’exception de l'indication de dépistage lorsque l’on considère les objets de très petits diamètres.L’étude de lecture humaine d’images simulées d’un fantôme anthropomorphique du sein incluant le rehaussement glandulaire physiologique et différents modèle tumoraux n’a pas montré d’augmentation significative de sensibilité de détection des acquisition 3D d’angiotomosynthèse comparativement aux acquisitions 2D d’angiomammographie. Les deux paramètres qui influençaient le plus la sensibilité était la concentration en iode des tumeurs et la densité du sein. L’angiomammographie était par ailleurs significativement plus spécifique que l’angiotomosynthèse. Une perspective d’amélioration pour l’angiotomosynthèse pourrait donc être l’utilisation d’algorithmes de reconstruction 3D spécifiques de cette modalité qui minimiseraient le bruit de reconstruction. Le scénario proposé pour la réalisation de biopsies sous guidage de l’angiomammographie, a mis en évidence deux contraintes techniques que sont l’échauffement du tube à rayons X et le surcroit de dose dû à la répétition des paires d’acquisitions en haute et basse énergies. Une des solutions envisagées a été de limiter le nombre d’acquisitions de BE. Notre étude a montré que la recombinaison d’une image HE avec une image BE acquise antérieurement modifiait le SDNR des lésions simulées comparativement à une recombinaison appariée d’images BE et HE acquises au même temps de l’injection. Ces modifications dépendaient du temps du pic de rehaussement maximal et du washout de la lésion. / Objectives: The purpose was to optimize the exposure parameters of CESM examinations, to assess the feasibility of contrast-enhanced DBT (CE-DBT) for the detection and the characterization of breast tumors, and to assess CESM-guided stereotactic biopsies. Methods: At first, we optimized the CESM exposure parameters in four different clinical applications for which different levels of average glandular dose and different low energy image quality are required. The optimization of exposure parameters (anode/filter, kVp, mAs) for low energy (LE) and high energy (HE) images at different levels of average glandular dose and different ratios between LE and total doses has been conducted using a simulator of the x-ray mammographic image chain. An experimental validation was then performed through phantom experiments. Secondly, we assessed the potential of CE-DBT based on a dual-energy approach. A new mesh-based anthropomorphic breast phantom was improved and used to evaluate the performance of CESM and then to compare CESM and CE-DBT. Finally, we evaluated the technical feasibility of CESM-guided biopsy. After identifying some technical constraints, we assessed the performance of the recombination of LE and HE images acquired at different times after injection, using simulated images of a geometric phantom with uniform texture, and simulated images of an anthropomorphic textured phantom with and without motion artifacts.Results and conclusion : For the four different clinical indications, optima found by simulation, with resulting SDNRpixel and SDNR2pixel/Dosetotal, were confirmed through real acquisition of images on phantoms. Our results indicate that the SDNR per pixel in recombined CESM images increased in all of the four clinical indications compared to recombined images obtained using SenoBright ® (commercial product used as reference). This result suggests the possibility to detect more subtle contrast enhancements and to decrease the number of false negatives found in clinical CESM examinations. The impact of a new dose allocation between LE and HE exposures was also evaluated on LE image quality. Results from CDMAM phantom experiments indicate that optimized parameters provide similar or acceptable detection compared to standard mammography, except for screening indication when considering the very small diameter objects.The human observer study on anthropomorphic phantom images, taking into account tumor and breast parenchyma enhancement, revealed that detection and characterization sensitivity of iodine-enhanced lesions are not statistically different between 2D CESM and 3D CE-DBT. The most influencing parameters for the detectability and the lesion size assessment were the lesion iodine concentration and the breast density. CESM was significantly more specific than CE-DBT. One of the assumptions to explain this result is the presence of higher noise in CE-DBT than in CESM images. A future improvement for CE-DBT could therefore be the design of a specific reconstruction algorithm minimizing reconstructed noise.With respect to CESM-guided biopsy the proposed scenario pointed out two major constraints, one related to the thermal load of the x-ray tube, the second related to the increased dose due to the repetition of LE and HE images. One proposed solution was to limit the number of LE exposures, requiring the possibility to recombined LE and HE images acquired at different injection time points. Our study showed that the recombination of a HE image with a LE image acquired earlier leads to SDNR changes compared to paired recombination. These changes are function of the enhancement time to peak and the washout of the lesion, and had a limited impact on the lesion detectability.

Τα υπολογιστικά συστήματα υποβοήθησης ανίχνευσης και διάγνωσης αλλοιώσεων του μαστού έχουν προταθεί στις διάφορες απεικονιστικές τεχνικές «ως δεύτεροι αναγνώστες» με σκοπό να αυξήσουν τη διαγνωστική ακρίβεια του ακτινολόγου και να μειώσουν τη μεταβλητότητα μεταξύ και ενδο-παρατηρητή κατά την ερμηνεία της μαστογραφικής εικόνας. Η αυτόματη διάγνωση των ομάδων μικροαποτιτανώσεων αποτελεί ανοικτό ερευνητικό ζήτημα. Τα προταθέντα συστήματα ψηφιακής υποβοήθησης διάγνωσης ομάδων μικροαποτιτανώσεων ακολουθούν δύο βασικές προσεγγίσεις: (α) ανάλυση μορφολογίας των μεμονωμένων μικροαποτιτανώσεων της ομάδας και (β) ανάλυση υφής των περιοχών ενδιαφέροντος της μαστογραφικής εικόνας που περικλείει την ομάδα μικροαποτιτανώσεων. Τα συστήματα αυτά διατυπώνουν μαθηματικά το κλινικό ερώτημα αξιοποιώντας μεθόδους επεξεργασίας και ανάλυσης εικόνας με σκοπό την ποσοτικοποίηση δομικών και λειτουργικών παραμέτρων του απεικονιζόμενου ιστού. Στην παρούσα εργασία περιγράφονται οι τρέχουσες προσεγγίσεις στην μεθοδολογία ανάπτυξης συστημάτων υποβοήθησης διάγνωσης ομάδων μικροαποτιτανώσεων στην μαστογραφία ακτίνων-Χ. Σκοπός είναι η ανάδειξη των πλεονεκτημάτων, μειονεκτημάτων και προκλήσεων των διαφορετικών προσεγγίσεων της ψηφιακής υποβοήθησης διάγνωσης, η καταγραφή των εξελίξεων και αναδυόμενων μεθόδων καθώς και η διερεύνηση και αποτύπωση των μελλοντικών ερευνητικών βημάτων. / Computer-aided detection and diagnosis schemes have been proposed across breast imaging modalities to improve diagnostic accuracy and reduce inter- and intra-observer variability in image interpretation. Computer-aided diagnosis schemes for microcalcification clusters in mammography are based on morphology analysis of individual microcalcifications and on texture analysis of the depicted breast tissue. The current study reviews major approaches in the development of computer-aided diagnosis schemes for microcalcification clusters in mammography, while recent advances and challenges of each methodological approach are highlighted.