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Dissertations / Theses on the topic 'Mammography'
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Marti, Robert. "Multi-modality mammography." Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251724.
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Coakley, Kerry Shona. "Phase contrast mammography." Thesis, Queensland University of Technology, 2000.
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Kessler, Cecilia. "Développement et mise en place au BIPM d’un systéme international de comparaison et d’étalonnage pour la dosimétrie en mammographie." Thesis, Paris, CNAM, 2013. http://www.theses.fr/2013CNAM0864/document.
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La mammographie est une technique d’imagerie par rayons x, considérée comme la technique actuelle la plus efficace pour dépister le cancer du sein à un stade précoce. A cause des risques de carcinogenèse induite par les rayonnements associés à l’examen par rayons x, il est donc essentiel de réaliser un étalonnage précis du faisceau de rayonnements afin de réduire au maximum la dose de rayonnement délivrée au sein du patient et d’obtenir la meilleure qualité d’image possible. L’étalonnage du faisceau de rayons x est effectué avec des chambres d’ionisation, instruments du commerce qui doivent être préalablement étalonnées dans des laboratoires d’étalonnage de référence, de préférence dans le même type de faisceaux de rayonnements que celui utilisé pour le diagnostic.Dans un pays donné, les laboratoires d’étalonnage de référence en dosimétrie des rayonnements sont généralement rattachés au laboratoire national de métrologie ; ce sont des laboratoires de référence primaires ou secondaires de dosimétrie. Les laboratoires primaires vérifient l’exactitude de leurs mesures conduites avec des étalons primaires en participant à des comparaisons internationales alors que les laboratoires secondaires, détenteurs d’étalons secondaires, doivent procéder à la caractérisation de leurs instruments de référence.Afin de répondre aux besoins des laboratoires nationaux de métrologie le Bureau international des poids et mesures (BIPM) maintient des étalons de référence stables pour la dosimétrie des rayonnements ionisants et met à disposition de ses États Membres des équipements internationaux pour la comparaison des étalons primaires et la caractérisation des étalons nationaux secondaires afin d’assurer l’unification mondiale des mesures et leur traçabilité au Système international d’unités (SI).Le Département des rayonnements ionisants du BIPM a effectué les premières comparaisons internationales dans des faisceaux de rayons x aux basses énergies en 1966 et, en 2001, les Instituts nationaux de métrologie (INM) ont pour la première fois proposé que le BIPM étende ses activités à la mammographie.Une description du travail que j’ai entrepris au BIPM pour répondre aux besoins des laboratoires nationaux de métrologie en matière de comparaisons et d’étalonnages dans ce domaine est présentée dans cette thèse et distribuée en quatre parties : l’établissement de sept faisceaux de rayonnement en utilisant un tube à rayons x à anode en tungstène et filtre en molybdène (faisceau W/Mo); l’installation d’un tube à rayons x à anode en molybdène avec filtre en molybdène et l’établissement de quatre faisceaux de rayonnement (faisceau Mo/Mo); conception et fabrication d’un nouvel étalon primaire pour la dosimétrie dans les faisceaux mammographiques. la création d’une nouvelle série de comparaisons en continu du BIPM, identifiées dans la base de données du BIPM sur les comparaisons clés KCDB sous la référence BIPM.RI(I)-K7 et un programme pour l’étalonnage des étalons nationaux secondaires qui inclut le nouveau dispositif expérimental dans le système managérial de la qualité du département des rayonnements ionisants (RI) du BIPM.L’expertise acquise lors de ce travail est maintenant transféré aux INM pour les aider dans le développement de leurs propres étalons primaires et à améliorer leurs dispositifs expérimentaux existants. Jusqu’à aujourd’hui 6 comparaisons ont été menées à bien dans le nouveau dispositif expérimental établi au BIPM ; la participation à la nouvelle comparaison–clé continue permet aux INM de soutenir leurs capacités d’étalonnages et de mesures (CMC). La caractérisation et l’étalonnage des étalons nationaux secondaires ont été réalisés pour l’heure pour 5 INMMammography is an x-ray examination of the breast, considered to be the most sensitive technique currently available for early detection of breast cancer. Because of risks of radiation-induced carcinogenesis associated with the use of x rays, accurate calibration of the x-ray unit is essential in order to minimize the radiation dose delivered to the patient breast but having a good image quality. The beam calibration is made using ionization chambers, commercial instruments that need to be characterized at standard reference dosimetry laboratories in well-defined x-ray beams similar to those used in the diagnostic institutes.Standard reference laboratories for radiation dosimetry are usually part of the National Metrology Institute of each country; they can either be Primary or Secondary Standard Dosimetry Laboratories. Primary Laboratories verify the accuracy of their measurements using the primary standards by taking part in international comparisons while the Secondary Laboratories, holding secondary standards, need the characterization of their reference instruments. In order to fulfil these requirements of the National Metrology Institutes (NMIs), the Bureau International des Poids et Mesures (BIPM) maintains stable reference standards for radiation dosimetry and provides to the its Member States an international facility for comparisons of primary standards and characterization of secondary standards to ensure world-wide uniformity of measurements and their traceability to the International System of Units (SI).The Ionizing Radiation Department of the BIPM started international comparisons and characterizations in low-energy x-ray beams in 1966 and in 2001, the NMIs required the BIPM to extend these activities to mammography beams. A description of the work I carried out at the BIPM to provide an international facility for comparisons and calibrations in the mammography field is presented in this thesis, divided into four stages: establishment of seven reference radiation beams using the combination tungsten-anode x-ray tube and molybdenum filtration (W/Mo beams); installation of a molybdenum-anode x-ray tube with molybdenum filtration and establishment of four reference radiation beams (Mo/Mo beams); design and construction of a new primary standard free-air chamber for the dosimetry of the mammography beams; establishment of a new ongoing international comparison in the new reference mammography beams, registered in the BIPM key comparison database KCDB as BIPM.RI(I)-K7 and a programme for the calibration of national secondary standards by including the new facility in the quality management system of the Ionizing Radiation (IR) Department of the BIPM.The experience obtained during this work is now transferred to the NMIs to help them in the development of primary standards and to improve their existing facilities.To date, six successfully comparisons have been carried out in the new facility established at the BIPM; the participation in the new ongoing key comparison allow the NMIs to support their calibration and measurement capabilities (CMCs). Characterization and calibration of national secondary standards have been done for five NMIs
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Li, Yanpeng. "Mammographic Density Assessment: Inter-Reader Variability And Novel Phantom Quantification." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13820.
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Aims: This thesis aims to investigate the level of consistency in radiologists’ mammographic density (MD) reporting and to investigate the reasons that lead to reporting variability, and then to develop novel, affordable phantom images to validate imaging parameters linked with MD assessment. Methods: Project one: 17 radiologists were asked to report the BI-RADS density category and to manually segment the areas they regarded as MD for 40 clinical images. The consistency in the BI-RADS density reporting was quantified, and the impact of MD segmentation was investigated. For radiologists’ MD segmentation, the variation was quantified and the impact of image appearance was explored. Project two: A set of 100 phantom images were generated. Phantoms were manufactured using various masses and distributions of fine steel-wool set within a gelatine base to simulate the glandular and adipose tissue. A clustered lumpy background noise was added to the phantom images to simulate more complex images. The correlations between the simulated fibroglandular tissue mass and a series of imaging parameters were explored. Results: For the BI-RADS density reporting, k=0.477 for the 17 participants. In 450 out of 656 paired cases (approx. 69%), the BI-RADS categories matched the MD segmentation categories. The range of MD segmentation areas varied from 7% to 73% across the 40 images. The mean gray level value for 8 bit images being 146±19 vs. 99±14 for common and variation areas respectively. For the phantom project, very strong correlation was found for the standard deviation of mean intensity for the whole phantom image (r = 0.83, p<0.01). For the selected dense regions, very strong were shown for percentage density (r = 0.91, p<0.01), and integrated density (r = 0.93, p<0.01). Very strong and significant correlations remained after the lumpy noise was added. Conclusion: There were large variations for both MD reporting and MD identification between radiologists. In addition to subjectivity in reporting a category, the variation in radiologist MD identification is another major reason that leads to inconsistency in density reporting. Using our novel and affordable phantom, in addition to percentage density, the integrated density and the standard deviation of mean intensity may be used to facilitate MD quantification.
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Finn, Jane Rebecca. "Digital image processing for mammography." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/8888.
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Gabe, Rhian. "Observational evaluation of service mammography." Thesis, Queen Mary, University of London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440554.
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Rogers, Donna Marie. "Space, place and mammography utilization /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487948807585408.
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Benevides, Luis Alberto do Rego. "Breast dosimetry in clinical mammography." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011521.
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Barnabò, Andrea. "Machine learning techniques for mammography applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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During this work we will use machine learning and deep learning techniques in order to face up to some medical problems where they can play a basic role. In particular we will apply these algorithms to some mammography issues. The thesis presents three main experiments that are described below. The first one consists of a classification between nipples and non-nipples images. In this part of the work we will build a dataset composed by images belonging to these two classes. The main purpose here will be to build a classifier able to distinguish between nipple and non-nipple images. Several machine learning algorithms based on different models such as Support Vector Machine and Convolutional Neural Networks will be used in order to perform this task. In this experiment we will note the better classification capacity of the model based on Convolutional Neural Network. In the following section we will confront with an harder and usefull problem: the classification of tumoral masses vs non-tumoral masses. Therefore we will use a dataset composed by these two classes of images. We will perform again a classification either with Support Vector Machine or Convolutional Neural Networks. During this experiment we will obtain excellent results with the Convolutional Neural Networks and Support Vector Machine combined with a scattering network representation. The last part of the thesis consist of a realization of a complete CADx system . Here we will combine the models trained in the previous part and we will compare the results obtained by using them with the state of art.
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Brooks, Kenneth W. "Automated analysis of mammography phantom images." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17900.
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Saifuddin, Sarene Chu. "Contrast agent mammography using spectroscopic detectors." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616487.
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World Health Organization (WHO) reported that breast cancer is the top cancer in women both in the developed and the developing countries. Although breast cancer is thought to be a disease of the developed countries, the incidence of breast cancer is increasing in developing countries, where the disease has becoming the lead ing cause of death. WHO added that the high mortality rates in less developed countries is mainly causes by majority of cases are diagnosed in late stages preventing curable treatment, as well as by the lack of adequate diagnosis and treatment facilities. Therefore, early tumour detection is very important in breast cancer management being able to improve the surviving rate. Many techniques to improve the detection of tumours in the breast have been developed in the last few years. Th is study is focusing on the dual-energy technique of contrast-enhanced digital mammography (CEDM) to aid in the detection and characterization of breast lesions. Standard dual-energy (K-edge subtraction) methodology requires two separate acquisitions to obtain two images, below and above the K-edge of a given contrast agent, and is typically implemented with a monochromatic X-ray source. This work in mammography proposes an approach using a polychromatic beam, providing for clinical applications with X-ray tubes. In particular, with a polychromatic beam produced by a microfocal X-ray source, this work is aimed at assessing the feasibility of K-edge subtraction (KES) mammography carried out in conjunction with an iodine-based contrast agent. Spectroscopic information is obtained using pixellated spectroscopic detectors.
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簡適悠 and Sik-yau Anita Kan. "A clinical audit of mammography screening." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41710113.
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Tang, Mengxing. "Image reconstruction in electrical impedance mammography." Thesis, De Montfort University, 2003. http://hdl.handle.net/2086/6260.
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Breast cancer continues to be a leading cause of death in Western countries. One of the most important approaches to reduce this mortality is to detect the cancer as early as possible. Although current diagnostic imaging modalities are able to give useful information for diagnosis, development of new imaging technique is highly desirable in order to detect breast cancer in an earlier stage. This is the motive of the present study of Electrical Impedance Mammography (ElM), which applies Electrical Impedance Tomography (EIT) to image human breasts. The overall aim of the whole project is to develop impedance imaging techniques and system for early detection of breast cancer. The aim of the studies reported in this thesis is twofold, to investigate methods of improving EIT image quality and the feasibility of EIT in breast cancer detection. Focusing on these aims the following work is reported: 1) The study of three different image reconstruction algorithms is described. In this work the image reconstruction results are compared and the most appropriate algorithm was chosen for the subsequent study of breast imaging. 2) An investigation of two important factors in EIT image reconstruction, the number of electrodes (NOE) and the number of conductivity basis functions (NOCBF) whose effects on EIT images have yet been studied in detail so far, are described. In this work the image reconstruction is analysed with different combinations of NOE and NOCBF using Singular Value Decomposition (SVD) and spectrum expansion theory. Finally suggestions are given on which configuration could offer better image quality in breast imaging3) A comprehensive investigation is reported regarding compatibility of different types of prior information and its effect on an iterative image reconstruction algorithm, based on which a novel method is proposed to improve EIT image quality. This method selects compatible prior information by observing the convergence behaviour of an image reconstruction algorithm. The principle, implementation, and results are detailed. Results indicate the effectiveness of this method. 4) A two-dimensional breast imaging simulation system is introduced. In this work several breast models with different physiological and pathological conditions are made, based on clinical in vitro measurements and Cole-Cole model. Images with different current frequencies are reconstructed and analysed. Results indicate the potential of detecting and identifying breast abnormality by EIT. 5) A preliminary study on 3D EIT and 3D electrode placement has been conducted. The mathematic principle and implementation of 3D EIT are described, followed by a study on the sensitivity of boundary measurements to the conductivity changes in a cylindrical object with 2 different types of electrode placement. Suggestions are given on optimal electrode placement in EIT breast imaging. Finally suggestions are gIven for future work. These include a) investigating appropriate electrode placement for different applications and corresponding current & voltage patterns; b) incorporating more prior information into ElM image reconstruction; c) designing a more precise 3D breast forward model; and d) investigating appropriate regularization for image reconstruction
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Locascio, Nicholas (Nicholas J. ). "Deep learning for clinical mammography screening." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113130.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
"June 2017." Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 37).
Breast cancer is the most common cancer among women worldwide. Today, the vast majority of breast cancers are diagnosed from screening mammography. Multiple randomized clinical studies have demonstrated that screening mammography can help reduce the number of deaths from breast cancer among women ages 40 to 74, especially for those over age 50 [4], and can provide women diagnosed with breast cancer more options for less aggressive treatment [7]. Screening mammography is the first entry into the funnel of clinical mammography. A screening mammogram can result in a suspicious finding, leading the patient to receive additional imaging, and even surgical biopsy if the additional imaging. Screening mammography, as the first part of this funnel, is a place for machine learning to have impact on the largest amount of patients. In this work, we apply machine learning models to tasks in clinical mammography such as density estimation, and Bi-Rads prediction.
by Nicholas Locascio.
M. Eng.
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Hartswood, Mark. "Human factors in computer-aided mammography." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/10939.
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Breast screening requires film readers to exercise considerable expertise when examining breast X-rays (or 'mammograms') for signs of malignancy. Understandably; errors are sometimes made, and the screening programme is continually investigating ways to improve detection performance. In recent years, interest has grown in using computer based prompting systems to assist with reading. Prompting systems use image analysis techniques to identify possible cancers within a digitised mammogram and cue film readers to their location with the aim of preventing cancers from being overlooked. A qualitative analysis of clinic work practices show reading to be a situated activity with important collaborative dimensions. Tensions were found to exist between making decision-making visible (hence rendering it accountable and providing a reference by which performance can be monitored) and the possibility of being biased by exposure to the decision processes of others. It is argued that use of PROMAM offers a similar mix of advantages and pitfalls, and that lessons can be learned for prompting from how these tensions are managed for conventional forms of evidence. In subsequent investigations of prompting it was found that readers' interpretation and use of PROMAM were often problematic. Readers often had difficulties understanding prompts, and used them in ways contingent on the particular problem at hand rather than purely to aid detection. It is argued that effective prompting is not only a problem of achieving sufficient system performance, but also one of ensuring prompts are comprehensible, accountable, and appropriately used. Achieving the latter requires an understanding of how readers make sense of prompts in the context of their conventional reading practice.
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Kan, Sik-yau Anita. "A clinical audit of mammography screening." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41710113.
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Soh, Bao Lin Pauline. "Test-Set Reading: Value to Mammography." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11557.
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Purpose: The purpose of this thesis is to understand the relationship between mammographic performance based on actual clinical reading and performances at screen read test-sets, as well as to examine the potential causal agents for any lack of correlation. Methods: This study was designed to encompass three facets. The first element investigated the extent to which test-set reading can represent actual clinical reporting in screening mammography. The second element examined the manner that the location where reading takes place and the availability of prior images can impact upon performance in breast test-set reading. The third element considered the reading workstation monitors and the viewing environment available within BreastScreen New South Wales centres to determine whether consistent reporting conditions were provided to breast screen readers. Results: Moderate or acceptable level of agreement (W = 0.69–0.73, P < 0.01) were shown between actual clinical reporting and test-set conditions when describing group performance. The agreement was enhanced when prior images were available. The location where reading takes place and the availability of prior images showed acceptable levels of agreement (W = 0.75–0.79, P < 0.001) between group performance although both factors had a varying impact when examining the results of individual reader. The final aspect demonstrated an overall good adherence of reading workstation monitors and the viewing environment to published guidelines. Conclusions: Test-set readings in clinical and laboratory settings can be used to represent radiologic group performance in the clinic to a reasonable level particularly if prior images are available. If individual efficacy is being examined, some observers do demonstrate differences between test-sets and clinical performance, as well as differences between test-set situations even when viewing conditions are generally adhering to international standards.
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Olsén, Christina. "Towards Automatic Image Analysis for Computerised Mammography." Doctoral thesis, Umeå University, Computing Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1657.
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Mammographic screening is an effective way to detect breast cancer. Early detection of breast cancer depends to a high degree on the adequacy of the mammogram from which the diagnosis is made. Today, most of the analysis of the mammogram is performed by radiologists. Computer-aided diagnosis (CAD) systems have been proposed as an aid to increase the efficiency and effectiveness of the screening procedure by automatically indicating abnormalities in the mammograms. However, in order for a CAD system to be stable and efficient, the input images need to be adequate. Criteria for adequacy include: high resolution, low image noise and high image contrast. Additionally, the breast needs to be adequately positioned and compressed to properly visualise the entire breast and especially the glandular tissue.
This thesis addresses questions regarding the automatic determination of mammogram adequacy with the focus on breast positioning and segmentation evaluation. The goal and, thus, the major technical challenge is to develop algorithms that support fully automatic quality checks. The relevant quality criteria are discussed in Chapter 2. The aim of this discussion is to compile a comprehensive list of necessary criteria that a system for automatic assessment of mammographic adequacy must satisfy. Chapter 3 gives an overview of research performed in computer-aided analysis of mammograms. It also provides basic knowledge about image analysis involved in the research area of computerized mammography in general, and in the papers of this thesis, in particular. In contrast, Chapter 4 describes basic knowledge about segmentation evaluation, which is a highly important component in image analysis. Papers I–IV propose algorithms for measuring the quality of a mammogram according to certain criteria and addresses problems related to them. A method for automatic analysis of the shape of the pectoralis muscle is presented in Paper I. Paper II proposes a fully automatic method for extracting the breast border. A geometric assumption used by radiologists is that the nipple is located at the point on the breast border being furthest away from the pectoralis muscle. This assumption is investigated in Paper III, and a method for automatically restricting the search area is proposed. There has been an increasing need to develop an automated segmentation algorithm for extracting the glandular tissue, where the majority of breast cancer occur. In Paper IV, a novel approach for solving this problem in a robust and accurate way is proposed. Paper V discusses the challenges involved in evaluating the quality of segmentation algorithms based on ground truths provided by an expert panel. A method to relate ground truths provided by several experts to each other in order to establish levels of agreement is proposed. Furthermore, this work is used to develop an algorithm that combines an ensemble of markings into one surrogate ground truth.
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Zeidan, Mohammad. "Assessment of Mean Glandular Dose in Mammography." Thesis, University of Canterbury. Department of Physics, 2009. http://hdl.handle.net/10092/2653.
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The mean glandular dose (MGD) was measured for a breast phantom by using molybdenum/molybdenum and molybdenum/rhodium target/filter combinations, at different kVp 26, 28 and 32 kilovolts. The phantom thickness was 7.5cm and was made of BR12 material. The change of dose was studied as a function of depth inside the phantom at different depths from the surface, namely 3.3, 4.3 and 5.3cm, by using TLDs. It was found that the MGD value for different combinations of beam quality (HVL) and energy (kVp) did not exceed the recommended values given by different protocols. The Mo/Rh target/filter required lower doses to achieve the same or better results compared with the Mo/Mo target/filter. The change in the surface dose as a function of kVp was more significant for Mo/Rh than for the Mo/Mo. Studying the change in dose within the breast, as a function of depth gives a better understanding of the interactions between radiation and tissue inside the breast. It should be noted that the MGD is a tool for optimization of the mammography parameters. However, the MGD should not be used directly to estimate the risk of determinable health effects from mammography. This will ultimately help to determine limits for the breast surface dose and a better understanding of cancer risk. In future work, we will try to measure the change of the dose as a function of depth by using more kVp, HVL, different breast composition and different target/filter combinations to give a wider picture for different situations.
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Olsén, Christina. "Towards Automatic Image Analysis for Computerised Mammography /." Umeå : Department of Computing Science, Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1657.
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Yip, Mary. "Image simulation framework for digital mammography systems." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531394.
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Chang, Sue-Ling. "Breast cancer subtypes and screening mammography sensitivity." Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30680/30680.pdf.
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Les cancers du sein peuvent être classifiés selon le statut de récepteur d’estrogène (RE), de récepteur de progestérone (RP), de récepteur HER2, ou selon quatre sous-types (Luminal A, Luminal B, HER2-enrichi, Triple-négatif) ayant des propriétés biologiques et cliniques différentes. La sensibilité du dépistage par mammographie pourrait varier selon ces types de cancers mais ceci n’est pas encore clair. L’agressivité de la tumeur, mesurée par le grade histologique pourrait expliquer cette association. Les types de cancers d’intervalle ont été comparés à ceux de cancers détectés par dépistage parmi 1536 cas infiltrants provenant d’un centre de référence de Québec. Les tumeurs RE-négatif, RP-négatif, HER2-positif, Luminal B, HER2-enrichi et TPN étaient tous plus fréquentes chez les femmes avec cancers d’intervalle que chez celles avec cancers détectés par dépistage. À l’exception des tumeurs HER2-positif et HER2-enrichi, le grade histologique expliquait en grande partie la variabilité observée entre les types de cancer et la sensibilité.Breast cancers can be classified according to tumour estrogen (ER) and progesterone (PR) receptors, human epidermal growth factor receptor 2 (HER2), and according to four subtypes (Luminal A, Luminal B, HER2-enriched, Triple-negative), each with different biological and clinical profiles. These tumour types may also influence screening mammography sensitivity but this is still not clear. Tumour aggressiveness, measured by the histological grade, may also play a role in explaining this association. Interval cancer types were compared to screen-detected cancer types in 1536 invasive cases obtained from a reference center in Quebec. ER-negative, PR-negative and HER2-positive, Luminal B, HER2-enriched and TPN tumours were all more frequent in women with interval cancers than in women with screen-detected cancers. Except for HER2-positive and HER2-enriched tumours, histological grade explained most of the variability observed between tumour receptor status, subtypes and sensitivity.
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Blot, Lilian. "Texture analysis and synthesis : applications in mammography." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396607.
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Price, B. D. "Towards combined X-ray and optical mammography." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1209181/.
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Optical contrast, dependent upon haemodynamics and thus providing physiological information, is complementary to radiographic contrast. Combined x-ray and optical mammography screening could provide increased specificity over either system alone. Medical imaging equipment is routinely characterised and tested using tissue equivalent phantoms. A novel phantom material is presented: a solution of polyvinyl alcohol in ethanol and water freeze-thawed to produce a solid yet elastically compressible gel. The x-ray attenuation, mechanical and optical properties of these gels can be accurately adjusted over appropriate ranges so as to mimic cancerous or healthy breast tissues. Modulated imaging in both optical and x-ray acquisitions is also considered. An x-ray system capable of optimising dose distribution has previously been developed at UCL. Overall images are obtained by aligning multiple images from smaller sensors. The effects that this type of acquisition has on spatial resolution are discussed. Two considerations are made: (i) is there a minimum size sensor whose modulation transfer function (MTF) can accurately be determined? (ii) does the MTF of an overall image differ significantly from those of its constituent images? The smaller a sensor becomes, the harder it is to determine its MTF accurately, and the resolution of overall images is slightly poorer than those of individual sensor images. Nonetheless these effects are small and should not hinder the development of such systems. Whilst similar dose considerations do not apply to optical tomography, modulated imaging still presents potential benefits. A method of visualising intensity data in order to localise regions of heterogenous absorption is presented using both simulated and experimental data. Objective functions designed to quantify the visibility of these heterogeneities are proposed and it is shown that optimal distributions of source power, that maximise these, can be found. It is proposed that such techniques might allow optical acquisitions to be performed more rapidly.
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Lease, Alyson. "Feasibility of using LODOX technology for mammography." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/3260.
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Kovalchuk, Nataliya. "Advances in Magnetic Resonance Electrical Impedance Mammography." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002443.
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Brown, Wendy L. "Emotional and pain responses to screening mammography /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16300.pdf.
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Hahn, Hee Il. "Wavelet transforms for detecting microcalcifications in mammography." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187416.
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A three-stage method based on wavelet transforms for detecting and segmenting calcifications is developed. The first stage consists of preprocessing which is realized by subtracting from the original image a Gaussian low-pass filtered version, followed by a full resolution wavelet transform. With a Laplacian of Gaussian wavelet basis the detection of microcalcifications can be nearly optimized in the details sub-bands. In fact, the two-dimensional filters which transform the input image into HH and LH + HL details sub-bands are closely related to prewhitening matched filters for detecting Gaussian objects in separable and non-separable first-order Markov noise, respectively. Two methods have been proposed to detect candidate microcalcifications. In the first method, the outputs HH and LH + HL from each octave are thresholded at some fixed percentile of the histogram of each component. Then, the detected images from all octaves are logically ORed to yield the binary map of detected pixels. The second method employs a Hotelling observer. The Hotelling discriminant is computed and then thresholded to obtain the binary map. The second stage is needed to reduce false alarms, which are reduced by analyzing the shapes of the detected pixel regions. The third stage is designed to provide an accurate segmentation of calcification boundaries. Individual microcalcifications are often greatly enhanced in the output image. FROC curves are computed from tests using a well-known database of digitized mammograms. The algorithm using the Hotelling observer shows the best overall performance in which a true positive fraction of 73% is achieved at 0.7 false positives per image.
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Damases, Christine. "Causal factors and potential clinical implications of variation in mammographic density assessment." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16141.
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The thesis explores various measures of MBD assessment in digital mammography (DM) and assesses inter-‐reader variability using BI-‐RADS® and RANZCR scales based on four studies. Methods: In studies 1 and 2, 40 images from 20 US women—acquired one year apart—were processed using Volpara®densityTM software. Observers (20 experts) assessed the images using BI-‐RADS®. Study 1 used spearman’s correlation (ρ) to examine relationships between the systems for BI-‐RADS®, VDG, and AvBD%. Study 2 examined inter-‐observer agreement using BI-‐RADS® 4-‐point and binary scales. In study 3, 26 Australian radiologists assessed 40 images using RANZCR synoptic scales. Agreement on RANZCR scales between radiologists was expressed as Cohen’s Kappa (κ). Study 4 used a weighted Kappa (κw) statistic to test for agreement between MBD assessment schemes and pairs of observers based on BI-‐RADS® scores from 20 ABR examiners, 24 UK practitioners, and RANZCR radiologists. Results: In study 1, both BI-‐RADS® (ρ=0.904; p<0.001) and Volpara (ρ=0.978; p<0.001) showed positive correlations between the systems. Study 2 reported BI-‐RADS® inter-‐reader agreement of 0.565 [95% CI=0.519–0.610] on the 4-‐point scale and 0.855 [95% CI=0.824–0.866] on the binary scale. Study 3 reported RANZCR inter-‐ reader agreement of 0.360 [95% CI=0.308–0.412] on the 4-‐point scale and 0.726 (95% CI=0.675–0.777) on the 2-‐point scale. Study 4 reported agreement (κw) of 0.10 [95% CI=-‐ 1.13–0.43] between ABR and RANZCR radiologists, 0.25[95% CI=-‐0.42–0.61] between ABR and UK practitioners, and 0.95 [95% CI=0.91–0.97] between RANZCR radiologists and UK practitioners. Conclusion: Results show lesser variation on binary scale than on 4-‐point scale for both BI-‐RADS® and RANZCR. Volpara®densityTM MBD measurement shows better agreement between the imaging systems than BI-‐RADS®. This work provides insight into potential implications of inconsistency in MBD assessment on breast cancer risk stratification.
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Gonzalez, Ana Paula Squaris. "Identificação de critérios de avaliação de tecnologias em saúde : estudo de caso em mamografia." reponame:Repositório Institucional da UFABC, 2015.
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Orientador: Prof. Dr. Harki TanakaDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Biomédica, 2015.
Esse trabalho visou realizar um estudo para auxiliar gestores de tecnologias médicas por meio da denição de critérios de avaliação de tecnologia em saúde na escolha de um equipamento de mamograa. O gestor de tecnologias médicas na atualidade encontra no mercado três tipos de tecnologias de mamograa diferentes: mamograa convencional, mamograa computadorizada e mamograa digital. Primeiramente foi realizado um estudo sobre a cadeia de imagem de cada tecnologia. A partir do conhecimento da cadeia de imagem de cada tecnologia, foi possível identicar cada processo característico de todas as tecnologias e com isso identicar a especicidade do custo gerado por essas modalidades em cada ponto. Alguns valores como custo de aquisição, custo de manutenção e custo de insumos foram coletados da Bolsa Eletrônica de Compras do Estado de São Paulo e no Diário Ocial da União. Características relacionadas à epidemiologia, sensibilidade e especicidade foram coletadas em estudos cientícos. Um estudo sobre a desinstalação e descarte foi realizado, levando-se em consideração as diretrizes para cada tecnologia. A m de nos aproximar da realidade do funcionamento de um mamógrafo, as diferentes tecnologias em mamograa foram inseridas em um contexto de uma clínica de imagens radiológicas. Para auxiliar a análise econômica foram desenvolvidas planilhas de cálculo eletrônico. A vida útil considerada para cada equipamento foi de 10 anos. O custo que representou maior impacto econômico foi o de recursos humanos em todas as tecnologias. A mamograa que apresentou o menor custo por exame foi a mamograa computadorizada sem impressão do lme (CRP), embora o custo de aquisição dos seus equipamentos seja aproximadamente quatro vezes maior que a mamograa convencional. A mamograa computadorizada quando existe a impressão do lme apresentou o maior valor por exame. Os estudos de acurácia e sensibilidade mostraram que a mamograa digital tem um pequeno ganho apenas em mulheres abaixo de 50 anos quando comparada à mamograa convencional.
This study aimed to help medical technology managers to choose mammography equipment through criteria of health technology assessment. The manager of medical technologies nds on the market today three dierent types of mammography technologies: conventional mammography, computerized mammography and digital mammography. First, we conducted a study on the image chain for each technology. From the knowledge of the image chain for each technology, it was possible to identify each characteristic process of all technologies and thereby identifying the specicity of the costs generated by such arrangements on each point. Some values as acquisition cost, maintenance cost and cost of inputs were collected from Electronic Trading Platforms of São Paulo state and in the Ocial Gazette of Brazil. Characteristics related to epidemiology, sensitivity and specicity were collected in scientic studies. A study on uninstalling and disposal was carried out, taking into account the guidelines for each technology. In order to approach the reality of the operation of a mammography unit, the dierent technologies in mammography were inserted in a context of clinical radiological images. To assist the economic analysis, electronic spreadsheets were developed. The lifetime considered for each equipment was 10 years. The greater economic impact was the cost of human resources in all technologies. A mammogram that showed the lowest cost per exam was computerized mammography without screen-lm (CRP), although the cost of purchasing of the equipment is approximately four times higher than conventional mammography. Computerized mammography, when there is the impression of the lm, has the highest cost per exam. The accuracy and sensitivity studies have shown that digital mammography has a small gain only in women under 50 years of age, when compared to conventional mammography.
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Yilmaz, Tugba. "Psychosocial Correlates Of Breast Self Examination And Mammography." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614639/index.pdf.
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The objective of this study was to examine the relationship between psychosocial correlates (big 5 personality traits, dispositional optimism, the Health Belief Model, breast cancer fear, mammography self efficacy, and social support) and breast self examination (BSE) and mammography in breast cancer-free women. In order to measure the social support of the participants, the MOS social support survey was adapted to Turkish culture in the scope of study 1. The sample of the study 1 included 241 participants. The analyses showed that Turkish version of the MOS social support survey had satisfactory psychometric properties. The sample of the study 2 was composed of 230 asymptomatic women for breast cancer. Independent samples t-test results indicated that among the Health Belief Model notions, perceived benefit, barrier, confidence, and health motivation significantly differentiated women who practiced BSE and who did not. However, the HBM notions were not able to differentiate women who had mammography and who did not have. Instead, social support significantly clarified the difference between
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women who had mammography and women who did not have. Two hierarchical logistic regression analyses were carried out for BSE and mammography. Big 5 personality traits and dispositional optimism were entered at the first step. The HBM factors and self efficacy were entered at the second step. Breast cancer fear was added at the third stepand for the last step social support measures were added to the equation. For BSE, hierarchical logistic regression yielded no significant predictors but BSE confidence and susceptibility from the HBM. For mammography, the hierarchical logistic analysis resulted that only functional support, which was entered at the fourth step was significant. The strengths and limitations, as well as the implications of the findings, were discussed.
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Dinh, Ngoc-Thy. "The Cost-Effectiveness of Screening Mammography in Canada." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32325.
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This work includes a series of studies that examines the health and economic impacts of screening mammography from international and Canadian perspectives. This work is a compendium of several researched chapters that include an introduction, four body chapters, and a discussion. The body chapters include a systematic review of the health economic literature on screening mammography, a review of quantitative models used to examine the consequences of breast cancer screening, and cost-effectiveness analyses of screening mammography programs in Canada for the general female population and for subgroups of the population at high-risk for breast cancer. There are three analytic chapters that will be submitted as manuscripts for peer-reviewed publication. The main results of this research show that current screening mammography practices in Canada may extend life at an acceptable cost to the health care system. Due to the outlined methodological limitations of this research the results should be interpreted with caution.
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Barnsley, G. Philip. "Evaluation of surveillance mammography following reconstructive breast surgery." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27811.
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Objective. There are currently no recommendations on the use of surveillance mammography for women who have undergone breast reconstruction following mastectomy. The objective of this study is to address the needs of this population of women with regards to the inclusion of ipsilateral surveillance mammography in their regular surveillance.
Methods. A multimethod approach including (1) a systematic review, (2) a population based cohort study, and (3) an economic analysis was conducted to evaluate this issue.
Results. The systematic review found only case reports and case series' addressing the role of surveillance mammography in women who have undergone breast reconstruction following mastectomy. These studies documented that local recurrence does occur in reconstructed breasts, and that these may be detected by surveillance mammography. In the cohort component of the study, variation in practice was found as 39% of women in the cohort underwent at least one surveillance mammogram of their reconstructed breast. Inference on the effectiveness of surveillance mammography of the reconstructed breast could not be made. The economic analysis found that in order to be cost effective, a reduction in metastatic risk of 3.34% following local recurrence detected by surveillance mammography was required.
Conclusion. The findings from this thesis point to two recommendations. First, until stronger evidence becomes available, it is prudent to recommend that women with breast reconstruction undergo yearly bilateral surveillance mammography. Second, future research is required to review patient outcomes and provide the needed clinical evidence to support this practice.
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Shen, Liang. "Region-based adaptive image processing techniques for mammography." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0011/NQ34701.pdf.
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Bornefalk, Hans. "Computer-aided detection and novel mammography imaging techniques." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3861.
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Lagerlund, Magdalena. "Factors affecting attendance at population-based mammography screening /." Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-061-x/.
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Hong, Byung-Woo. "Image segmentation, shape and registration : application to mammography." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413508.
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White, Laura Louise. "Theoretical and experimental studies in positron emission mammography." Thesis, Institute of Cancer Research (University Of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404997.
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Sze, Gerald. "Detection of breast cancer with electrical impedance mammography." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/39460/.
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Electrical Impedance Tomography (EIT) is a medical imaging technique that reconstructs internal electrical conductivity distribution of a body from impedance data that is measured on the body surface, and Electrical Impedance Mammography (EIM) is the technique that applies EIT in breast cancer detection. The use of EIM for breast cancer identification is highly desirable because it is a non-invasive and low-cost imaging technology. EIM has the potential in detecting early stage cancer, however there are still challenges that hindering EIM to be provided as a routine health care system. There are three major groups of obstacles. One is the hardware design, which includes the selection of electronic components, electrode-skin contacting methods, etc. Second is theoretical problems such as electrode configurations, image reconstruction and regularization methods. Third is the development of analysis methods and generation of a cancerous tissue database. Research reported in this thesis strives to understand these problems and aims to provide possible solutions to build a clinical EIM system. The studies are carried out in four parts. First the functionalities of the Sussex Mk4 EIM system have been studied. Sensitivity of the system was investigated to find out the strength and weakness of the system. Then work has been made on image reconstruction and regularization methods in order to enhance the system's endurance to noise, also to balance the reconstruction conductivity distribution throughout the reconstructed object. Then a novel cancer diagnosis technique was proposed. It was developed based on the electrical property of human breast tissue and the behaviour or systematic noise, to provide repeatable results for each patient. Finally evaluation has been made on previous EIM systems to find out the major problems. Based on sensitivity analysis, an optimal combined electrode configuration has been proposed to improve sensitivity. The system has been developed and produced meaningful clinical images. The work makes significant contributions to society. This novel cancer diagnosis method has high accuracy for cancer identification. The combined electrode configuration has also provided flexibilities in the designing of current driving and voltage receiving patterns, thus sensitivity of the EIM system can be greatly improved.
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Richardson, Richard Thomas. "Image Enhancement of Cancerous Tissue in Mammography Images." NSUWorks, 2015. http://nsuworks.nova.edu/gscis_etd/39.
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This research presents a framework for enhancing and analyzing time-sequenced mammographic images for detection of cancerous tissue, specifically designed to assist radiologists and physicians with the detection of breast cancer. By using computer aided diagnosis (CAD) systems as a tool to help in the detection of breast cancer in computed tomography (CT) mammography images, previous CT mammography images will enhance the interpretation of the next series of images. The first stage of this dissertation applies image subtraction to images from the same patient over time. Image types are defined as temporal subtraction, dual-energy subtraction, and Digital Database for Screening Mammography (DDSM). Image enhancement begins by applying image registration and subtraction using Matlab 2012a registration for temporal images and dual-energy subtraction for dual-energy images. DDSM images require no registration or subtraction as they are used for baseline analysis. The image data are from three different sources and all images had been annotated by radiologists for each image type using an image mask to identify malignant and benign.
The second stage involved the examination of four different thresholding techniques. The amplitude thresholding method manipulates objects and backgrounds in such a way that object and background pixels have grey levels grouped into two dominant and different modes. In these cases, it was possible to extract the objects from the background using a threshold that separates the modes. The local thresholding introduced posed no restrictions on region shape or size, because it maximized edge features by thresholding local regions separately. The overall histogram analysis showed minima and maxima of the image and provided four feature types--mean, variance, skewness, and kurtosis. K-means clustering provided sequential splitting, initially performing dynamic splits. These dynamic splits were then further split into smaller, more variant regions until the regions of interest were isolated. Regional-growing methods used recursive splitting to partition the image top-down by using the average brightness of a region. Each thresholding method was applied to each of the three image types.
In the final stage, the training set and test set were derived by applying the four thresholding methods on each of the three image types. This was accomplished by running Matlab 2012a grey-level, co-occurrence matrix (GLCM) and utilizing 21 target feature types, which were obtained from the Matlab function texture features. An additional four feature types were obtained from the state of the histogram-based features types. These 25 feature types were applied to each of the two classifications malignant and benign. WEKA 3.6.10 was used along with classifier J48 and cross-validation 10 fold to find the precision, recall, and f-measure values. Best results were obtained from these two combinations: temporal subtraction with amplitude thresholding, and temporal subtraction with regional-growing thresholding. To summarize, the researcher's contribution was to assess the effectiveness of various thresholding methods in the context of a three-stage approach, to help radiologists find cancerous tissue lesions in CT and MRI mammography images.
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Ali, Raed Mohammed Kadhim M. "Risk of radiation-induced cancer from screening mammography." Thesis, University of Salford, 2016. http://usir.salford.ac.uk/41581/.
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Background and Objectives: When the benefits and risks of mammography are considered, the risk of radiation-induced cancer is calculated only for the breast using the mean glandular dose (MGD). Whilst MGD is a useful concept, it has many limitations. This thesis aims to establish a novel method to determine and convey radiation risk from full field digital mammography (FFDM) screening using lifetime effective risk. Method: For effective risk calculations, organ doses as well as examined breast MGD are required. Screening mammography was simulated by exposing a breast phantom for cranio-caudal and medio-lateral oblique for each breast using 16 FFDM machines. An anthropomorphic dosimetry phantom loaded with thermo-luminescent detectors (TLDs) was positioned in contact with the breast phantom to simulate the client’s body. Once the risk per individual was calculated, total effective lifetime risk across 48 worldwide screening programmes was calculated. The total effective risk data sets were analysed to establish a regression model to predict the effective risk of any screening programme. Graphs were generated to extrapolate the total effective risk of any screening programme of specific screening commencement age and frequency considering the MGD differences of different FFDM machines. Since the highest radiation dose after examined breast was received by contralateral breast, the effect of a contralateral breast lead shield on effective risk was also investigated. Results: Large differences in the effective lifetime risk exist between worldwide screening programmes. The effective lifetime risk varied from approximately 50 cases/106 to more than 1000 cases/106. These differences were mainly attributed to the commencement age and frequency of screening. Since tissue radio-sensitivity reduces with age, the cessation age of screening mammography does not result in a noteworthy effect on the total effective risk. The use of contralateral breast shield reduces the total effective risk by about 1.5% for most worldwide screening programmes. Conclusion: A novel method has been proposed to assess radiation-induced cancer risk from FFDM screening which considers the radiation dose received by all body tissues in addition to the examined breast. Using effective risk, the data is more likely to be understandable by screening clients and referring clinicians, unlike MGD which is not readily available or understandable by the general populace. This novel method and the data are compatible with the incoming European Commission legislation about giving the patient information on radiation risk.
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Tao, Wang. "Adapting multiple datasets for better mammography tumor detection." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231867.
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In Sweden, women of age between of 40 and 74 go through regular screening of their breasts every 18-24 months. The screening mainly involves obtaining a mammogram and having radiologists analyze them to detect any sign of breast cancer. However reading a mammography image requires experienced radiologist, and the lack of radiologist reduces the hospital's operating efficiency. What's more, mammography from different facilities increases the difficulty of diagnosis. Our work proposed a deep learning segmentation system which could adapt to mammography from various facilities and locate the position of the tumor. We train and test our method on two public mammography datasets and do several experiments to find the best parameter setting for our system. The test segmentation results suggest that our system could play as an auxiliary diagnosis tool for breast cancer diagnosis and improves diagnostic accuracy and efficiency.I Sverige går kvinnor i åldrarna mellan 40 och 74 igenom regelbunden screening av sina bröst med 18-24 månaders mellanrum. Screeningen innbär huvudsakligen att ta mammogram och att låta radiologer analysera dem för att upptäcka tecken på bröstcancer. Emellertid krävs det en erfaren radiolog för att tyda en mammografibild, och bristen på radiologer reducerar sjukhusets operativa effektivitet. Dessutom, att mammografin kommer från olika anläggningar ökar svårigheten att diagnostisera. Vårt arbete föreslår ett djuplärande segmenteringssystem som kan anpassa sig till mammografi från olika anläggningar och lokalisera tumörens position. Vi tränar och testar vår metod på två offentliga mammografidataset och gör flera experiment för att hitta den bästa parameterinställningen för vårt system. Testsegmenteringsresultaten tyder på att vårt system kan fungera som ett hjälpdiagnosverktyg vid diagnos av bröstcancer och förbättra diagnostisk noggrannhet och effektivitet.
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Suleiman, Mo'ayyad Essa Abedulrahman. "Diagnostic Reference Levels for digital mammography in Australia." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18930.
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Aims: In 3 phases, this thesis explores: radiation doses delivered to women during mammography, methods to estimate mean glandular dose (MGD), and the use of mammographic breast density (MBD) in MGD calculations. Firstly, it examines Diagnostic reference levels (DRLs) for digital mammography in Australia, with novel focus on the use of compressed breast thickness (CBT) and detector technologies as a guide when determining patient derived DRLs. Secondly, it analyses the agreement between Organ Dose estimated by different digital mammography units and calculated MGD for clinical data. Thirdly, it explores the novel use of MBD in MGD calculations, suggesting a new dose estimation called the actual glandular dose (AGD), and compares MGD to AGD. Methods: DICOM headers were extracted from 52405 anonymised mammograms using 3rd party software. Exposure and QA information were utilised to calculate MGD using 3 methods. LIBRA software was used to estimate MBD for 31097 mammograms. Median, 75th and 95th percentiles were calculated across MGDs obtained for all included data and according to 9 CBT ranges, average population CBT, and for 3 detector technologies. The significance of the differences, correlations, and agreement between MGDs for different CBT ranges, calculation methods, and different density estimation methods were analysed. Conclusions: This thesis have recommended DRLs for mammography in Australia, it shows that MGD is dependent upon CBT and detector technology, hence DRLs were presented as a table for different CBTs and detectors. The work also shows that Organ Doses reported by vendors vary from that calculated using established methodologies. Data produced also show that the use of MGD calculated using standardised glandularities underestimates dose at lower CBTs compared to AGD by up to 10%, hence, underestimating radiation risk. Finally, AGD was proposed; it considers differences in breast composition for individualised radiation-induced risk assessment.
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Turnbull, Deborah Anne. "Psychosocial issues in implementing mammography screening in Australia." Phd thesis, Faculty of Arts, 1992. http://hdl.handle.net/2123/8575.
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Stewart, Brian D. "Automatic mammogram interpretation using knowledge-based computer vision." Thesis, University of Dundee, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333875.
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Konstantinos, Marias. "Registration and quantitative comparison of temporal mammograms (with application to HRT data)." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271678.
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Riza, Eleni. "Determinants of mammographic parenchymal patterns and implications for breast cancer aetiology : a study in northern Greece (Ormylia Mammography Screening Programme)." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324626.
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García, Marcos Eloy. "Glandular tissue pattern analysis through multimodal MRI-mammography registration." Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/585969.
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Breast cancer is the most common cancer among women worldwide. Several studies have shown that the combination of the different medical image modalities, such as the x-ray mammography and the magnetic resonance imaging (MRI), leads to a more accurate diagnosis. The aim of this thesis is double, on the one hand, to evaluate the similarity between the information obtained from x-ray mammography and from MRI images and, on the other hand, to propose new registration algorithms to perform the correlation between the two image modalities. The problem includes from the biomechanical model construction, obtained from the MRI volume, the mechanical deformation, which is performed during the mammographic acquisition, the x-ray beam simulation traversing the breast in order to obtain the image (pseudo-mammogram) and the registration process to improve the similarity between the real and the synthetic imagesEl càncer de mama és el tipus de càncer més comú entre les dones de tot el món. Diversos estudis han demostrat que la combinació de diferents modalitats d'imatge mèdica, com ara la mamografia i la ressonància magnètica (MRI), comporta un diagnòstic més precís. L'objectiu d'aquesta tesi és doble, per una banda avaluar la similitud de la informació entre la mamografia de raigs X i la MRI i, d’altra banda, proposar nous algoritmes de registre que serveixin per a correlacionar la posició espacial en les dues modalitats d'imatge. El problema abarca la construcció del model biomecànic de la mama a partir de la ressonància magnètica, la simulació de la deformació que pateix la mama durant l’adquisició mamogràfica, la simulació dels rajos X atravessant la mama fins a obtenir la imatge (pseudo-mamografia) i els mètodes de registre posteriors per tal de millorar la similitud entre la imatge real i la simulada
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Dolan, Rachel Marie. "Racial disparities in mammography utilization in women under 40." Connect to Electronic Thesis (CONTENTdm), 2010. http://worldcat.org/oclc/646026423/viewonline.
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Sinzinger, Fabian. "Mammography Classification and Nodule Detection using Deep Neural Networks." Thesis, KTH, Numerisk analys, NA, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-220319.
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Mammographic screenings are the most common modality for an early detection of breast cancer, but a robust annotation of the depicted breast tissue presents an ongoing challenge, even for well-experienced radiologists. Computer-aided diagnosis systems can support the human classification. Modern systems therefore often rely on deep-learning based methods. This thesis investigates the fully automatic on-image classification of mammograms into one of the classes benign, malignant (cancerous) or normal. In this context, we compare two different design paradigms, one straightforward end-to-end model with a more complex decomposition hierarchy. While the end-to-end model consists mainly of the deep-learning based classifier, the decomposition pipeline incorporates multiple stages i.e. a region of interest detection (realized as a fully convolutional architecture) followed by a classification stage. Contrary to initial expectations, the end-to-end classifier turned out to obtain a superior performance in terms of accuracy (end-to-end: 76.57 %, decomposition: 65.66 %, computed as mean over all three classes in a one vs. all evaluation) and an improved area under receiver operating characteristic-score. All discussed parametric models were trained from scratch without using pre-trained network weights. Therefore we discuss the choice of hyper-parameters, initialization, and choice of a feasible cost function. For a successful feature extraction, in the region of interest detection stage, the negative dice coefficient proved itself to be a more robust cost function than the also investigated sensitivity-specificity loss.Mammografiscreening är den vanligaste modaliteten för tidig detektion av bröstcancer, men en robust annotering av den avbildade bröstvävnaden innebär en fortgående utmaning, till och med för en erfaren radiolog. Datorstödda diagnossystem kan bistå den mänskliga klassifikationen. Moderna system lutar sig därför ofta på datorbaserade metoder för djupinlärning. Den här avhandlingen undersöker den fullt automatiserade ”on-image” klassifikationen av mammogram i klasserna benign, malignt (cancer) eller normal. I denna kontext undersöker vi två olika design paradigm, en direkt end-to-end modell med en mer komplex dekomposition-hierarki. Medan end-to-end-modellen främst består av en deep-learning-baserad klassificerare består decomposition-pipelinen av flera steg, d.v.s. en detektion av en intresseregion (implementerad som en fullt faltningsoperations- neuralnätverk), följt av ett klassificeringsstadium. Till skillnad från initiala förväntningar visade sig det att end-to-end-klassificeraren erhöll en överlägsen prestanda när det gäller noggrannhet (end-to-end: 76.57 %, dekomposition: 65.66 %, mätvärdena är beräknade som medel av alla tre klasser i en en-mot-alla-utvärdering) och en förbättrad area-under-mottagare-operations karaktäristik. Alla behandlade parametriska modeller tränades initialt utan användning av förtränade nätverksvariabler. Därför diskuteras valet av hyper-parametrar, initiering, och val av rimlig kostnadsfunktion. För en funktionsextraktion, vid detektionsstadium i regionen av intresse, visade sig den negativa dice koefficienten vara en mer robust kostnadsfunktion än den också undersökta sensitivity-specifity loss.