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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Breast tumor size at first presentation in Haitian breast cancer patients treated in a large U.S. safety net hospital: initial

Hashm, Faoz Abdulsalam A. 02 November 2017 (has links)
This study assessed the tumor size at the time of first presentation of Haitian breast cancer patients compared to Non-Haitian Black and White patient populations of a large safety net hospital as an objective measure of diagnosis and treatment delay. Studies have shown that race and ethnicity have an influence in determining the breast cancer stage, treatment, and mortality rates. However, when we looked at the rates of breast cancer, screening among Black subgroups, such as Haitian women, was assessed and remained unclear because national studies do not differentiate Haitians from other Black populations. Two population-based studies that investigated breast cancer screening among Haitian women suggest that screening rates among Haitian women are lower than that of White and Black women. For this reason, many studies are diagnosed at later stages. This study to aimed to improved patient education. In this IRB approved retrospective study used the hospital electronic medical records and the cancer registry of breast cancer patients treated between 2013-2015. Female and male patients with primary breast cancer treated with surgery, complete imaging and medical data sets were included; patients with recurrent breast cancer or incomplete data sets were excluded. Demographics/race/ethnicity, tumor type and stage, receptor status, onco-type, proliferation rate as well as tumor size by radiology and pathology were recorded. vii Statistical analysis using ANOVA, T-test, U-test and Kruskal-Wallis, compared mean and median tumor sizes. In this study only tumor size was analyzed and reported. The results show 57/125 (45.6%) Haitian Black patients, 27/125 (21.6%) Non-Hispanic White, 41/125 (32.8%), Non-Haitian Black were included in the initial analysis of this study. The mean tumor size of Haitian Black (mean=3.09 cm, SD 2.91; median=2.3cm) was significantly larger compared to Black (mean=2.07cm, SD=1.77; median=1.6cm; p=0.022) or White (mean=1.88, SD=1.26; median=1.4; p = 0.008) patients. There was no significant difference in tumor size between Non-Haitian Black and White patients. Haitian Breast Cancer patients present with significantly larger tumors when compared to other patient populations. Improved patient education and intensified out-reach programs are needed to counteract this marked delay in initial diagnosis and treatment. Education and socio-economic differences must be further evaluated and all possible cofactors are needed to determine the most effective interaction to counteract this disparity.
42

MICROWAVE IMAGING OF BIOLOGICAL TISSUES: applied toward breast tumor detection

Gunnarsson, Tommy January 2007 (has links)
<p>Microwave imaging is an efficient diagnostic modality for non-invasively visualizing dielectric contrasts of non-metallic bodies. An increasing interest of this field has been observed during the last decades. Many application areas in biomedicine have been issued, recently the breast tumor detection application using microwave imaging.</p><p>Many groups are working in the field at the moment for several reasons. Breast cancer is a major health problem globally for women, while it is the second most common cancer form for women causing 0.3 % of the yearly female death in Sweden. Medical imaging is considered as the most effective way of diagnostic breast tumors, where X-ray mammography is the dominating technique. However, this imaging modality still suffers from some limitations. Many women, mostly young ones, have radiographically dense breasts, which means that the breast tissues containing high rates of fibroglandular tissues. In this case the density is very similar to the breast tumor and the diagnosis is very difficult. In this case alternative modalities like Magnetic Resonance Imaging (MRI) with contrast enhancement and Ultrasound imaging are used, however those are not suitable for large scale screening program.Another limitation is the false-negative and false-positive rate using mammography, in general 5–15 % of the tumors are not detected and many cases have to go though a breast biopsy to verify a tumor diagnosis. At last the mammography using breast compression sometimes painful, and utilizing ionizing X-rays. The big potential in microwave imaging is the reported high contrast of complex permittivity between fibroglandular tissues and tumor tissues in breasts and that it is a non-ionizing method which probably will be rather inexpensive.</p><p>The goal with this work is to develop a microwave imaging system able to reconstruct quantitative images of a female breast. In the frame of this goal this Licentiate thesis contains a brief review of the ongoing research in the field of microwave imaging of biological tissues, with the major focus on the breast tumor application. Both imaging algorithms and experimental setups are included. A feasibility study is performed to analyze what response levels could be expected, in signal properties, in a breast tumor detection application. Also, the usability of a 3D microwave propagation simulator, (QW3D), in the setup development is investigated. This is done by using a simple antenna setup with a breast phantom with different tumor positions. From those results it is clear that strong responses are obtained by a tumor presence and the diffracted responses gives strong information about inhomogeneities inside the breast. The second part of this Licentiate thesis is done in collaboration between Mälardalen University and Supélec. Using the existing planar 2.45 GHz microwave camera and the iterative non-linear Newton Kantorovich code, developed at Département de Recherches en Electromagnétisme (DRE) at Supélec, as a starting point, a new platform for both real-time qualitative imaging and quantitative images of inhomogeneous objects are investigated. The focusing is related to breast tumor detection. For the moment the tomographic performance of the planar camera is verified in simulations through a comparison with other setups. Good calibration is observed, but still experimental work concerning phantom development etc. is needed before experimental results on breast tumor detection may be obtained.</p>
43

MICROWAVE IMAGING OF BIOLOGICAL TISSUES: applied toward breast tumor detection

Gunnarsson, Tommy January 2007 (has links)
Microwave imaging is an efficient diagnostic modality for non-invasively visualizing dielectric contrasts of non-metallic bodies. An increasing interest of this field has been observed during the last decades. Many application areas in biomedicine have been issued, recently the breast tumor detection application using microwave imaging. Many groups are working in the field at the moment for several reasons. Breast cancer is a major health problem globally for women, while it is the second most common cancer form for women causing 0.3 % of the yearly female death in Sweden. Medical imaging is considered as the most effective way of diagnostic breast tumors, where X-ray mammography is the dominating technique. However, this imaging modality still suffers from some limitations. Many women, mostly young ones, have radiographically dense breasts, which means that the breast tissues containing high rates of fibroglandular tissues. In this case the density is very similar to the breast tumor and the diagnosis is very difficult. In this case alternative modalities like Magnetic Resonance Imaging (MRI) with contrast enhancement and Ultrasound imaging are used, however those are not suitable for large scale screening program.Another limitation is the false-negative and false-positive rate using mammography, in general 5–15 % of the tumors are not detected and many cases have to go though a breast biopsy to verify a tumor diagnosis. At last the mammography using breast compression sometimes painful, and utilizing ionizing X-rays. The big potential in microwave imaging is the reported high contrast of complex permittivity between fibroglandular tissues and tumor tissues in breasts and that it is a non-ionizing method which probably will be rather inexpensive. The goal with this work is to develop a microwave imaging system able to reconstruct quantitative images of a female breast. In the frame of this goal this Licentiate thesis contains a brief review of the ongoing research in the field of microwave imaging of biological tissues, with the major focus on the breast tumor application. Both imaging algorithms and experimental setups are included. A feasibility study is performed to analyze what response levels could be expected, in signal properties, in a breast tumor detection application. Also, the usability of a 3D microwave propagation simulator, (QW3D), in the setup development is investigated. This is done by using a simple antenna setup with a breast phantom with different tumor positions. From those results it is clear that strong responses are obtained by a tumor presence and the diffracted responses gives strong information about inhomogeneities inside the breast. The second part of this Licentiate thesis is done in collaboration between Mälardalen University and Supélec. Using the existing planar 2.45 GHz microwave camera and the iterative non-linear Newton Kantorovich code, developed at Département de Recherches en Electromagnétisme (DRE) at Supélec, as a starting point, a new platform for both real-time qualitative imaging and quantitative images of inhomogeneous objects are investigated. The focusing is related to breast tumor detection. For the moment the tomographic performance of the planar camera is verified in simulations through a comparison with other setups. Good calibration is observed, but still experimental work concerning phantom development etc. is needed before experimental results on breast tumor detection may be obtained.
44

A multi-prism lens for hard X-Rays

Cederström, Björn January 2002 (has links)
This thesis describes a new type of refractive lens for hardx-rays. It is shown that a linear array of prisms, slightlyinclined with respect to the optical axis, will form a linefocus at a certain distance from the lens. Hence, the namemulti-prism lens. These lenses are free from sphericalaberration and are similar to planar parabolic compoundrefractive lenses in terms of performance. However, theydistinguish themselves in that only planar surfaces need to befabricated. A special feature is that the focal length can beeasily varied by adjusting the inclination angle. Theoretical calculations, based on geometrical and physicaloptics, are used to characterize the lenses. Aberrations arediscussed, as well as the sensitivity to fabricationimperfections, and insufficient flatness is identified as apotential problem. Ray-tracing is used to test theapproximations and assumptions used in the theory. Applicationsin x-ray microscopy and mammography are discussed. Lenses have been made of beryllium, silicon, epoxy anddiamond using different methods. Results from measurements ofsurface roughness and figure error show that the imperfectionsof the silicon and epoxy lenses should have a small impact,while the beryllium lenses should suffer from strongscattering. Experiments were performed at the EuropeanSynchrotron Radiation Facility and sub-µm focal linewidths, close to theoretical expectations, were measured forsilicon and epoxy lenses at 30 keV and 14 keV, respectively.Insertion gains up to 40 were reached. Two crossed lenses wereused to obtain focusing in two dimensions and a point focus.The smallest measured focal spot size was 1.0 µm by 5 .4µm, and an insertion gain exceeding 100 was achieved usingepoxy lenses. The diamond lenses suffered from voids in the materialformed in the chemical vapor deposition process, butnevertheless provided focal lines less than 2 µm in width,albeit at at relatively low insertion gain of 13. Due to theirexcellent thermal properties, these lenses are put forward ascandidates for optics at the next generationultra-high-intensity synchrotron beams and x-ray free electronlasers. Keywords:x-ray, optics, refractive, lens, mammography,synchrotron. / QC 20100524
45

Factors condicionants de la participació en un programa poblacional de detecció precoç del càncer de mama

Segura Noguera, Josep Maria 12 December 2001 (has links)
L'inici del programa de detecció precoç del càncer de mama en els districtes de Ciutat Vella i Sant Martí de la ciutat de Barcelona, va motivar la realització del primer estudi en el barri de la Barceloneta, amb l'objectiu d'analitzar diferents factors associats a la participació. La resposta després de la primera citació ha estat del 65%. S'ha relacionat amb l'historial clínic previ augmentant en quasi 4 vegades l'ods de resposta, i amb el receptor de la carta de citació, variant del 75% quan és la mateixa interessada fins el 47% quan la carta és dipositada a la bústia, i el 32% quan l'adreça és insegura. La resposta després de les citacions successives ha estat del 26%. S'ha relacionat amb l'historial clínic previ augmentant en quasi 8 vegades l'ods de resposta, i amb la raó de no haver vingut després de la primera citació, passant del 50% quan és circumstancial fins el 11% quan s'atribueix a manca d'interès. La taxa de cobertura (79%) disminueix amb l'edat, i augmenta amb el nivell educatiu.El segon estudi permet apreciar com prèviament al programa les mamografies no s'adequaven a les directrius europees. Un 59% de les dones entrevistades dels barris El Clot, Camp de l'Arpa i La Verneda, s'han fet una mamografia de cribratge en els últims quatre anys. Existeix una major utilització en dones més joves, de major nivell educatiu i que tenen historial clínic. La periodicitat era anyal en un 35%, biennal en un 38% i cada 2-4 anys en el 27% restant. El 58% de les mamografies s'han realitzat en la sanitat pública, que mostra el major percentatge (42%) de periodicitat biennal. En les dones participants, la visita al ginecòleg i la pràctica de citologia uterina han presentat la major associació (probabilitats 4 vegades superiors) amb la mamografia prèvia de cribratge. També s'han associat a una major utilització els antecedents personals de patologia mamària i familiars de càncer de mama, l'autoexploració mamària i la visita mèdica recent, mentre que l'autopercepció de salut ha presentat una relació inversa.Finalment, el tercer estudi és un assaig controlat aleatoritzat on s'han comparat tres diferents estratègies utilitzades per a invitar dones d'entre 50 a 64 anys a participar en el programa. L'estratègia del contacte directe incrementa de forma significativa fins un 22% la probabilitat de resposta després de la primera citació en les dones del barri de Raval Nord invitades. En el grup de contacte directe aquesta resposta era del 63%, comparat amb un 55% quan la carta era enviada pels professionals sanitaris del CAP, i un 52% quan era remesa pels responsables del programa. Aquest increment en el grup de contacte directe s'observa encara que sols s'ha aconseguit contactar en un 45% dels casos directament amb la mateixa dona. Quan aquest fet s'assoleix la resposta és del 72%. La utilització de professionals no sanitaris per a aconsellar les dones sembla ser una estratègia efectiva, particularment entre les dones de baix nivell educatiu. / The beginning of the breast cancer screening program in the Ciutat Vella and Sant Martí districts of Barcelona was the origin of the first study in the Barceloneta quarter, with the aim of analyzing different factors related to participation. The response after the first citation was 65%. Having a previous clinical history, increased in nearly 4 times the response odds. Response after the first citation was influenced by who the recipient of the citation letter was, ranging from 75% when this was the same person concerned to 47% when the letter was left in the letter-box, and to 32% when the address was uncertain. The response after subsequent citations was 26%. Having previous clinical history increased the response odds in almost 8 times. The response after successive citations, ranged from 50% when it was for circumstantial reasons, to 11 % when it was due to lack of interest. Coverage rate (79%) decreased with age, and increased with education level.The second study shows that, previously to the program, mammography screening did not comply with European guidelines. A screening mammography had been performed on 59 % of women interviewed in the El Clot, Camp de l'Arpa and La Verneda quarters. The utilization of mammography was higher among younger women, women with a higher education level, or who had previous visits to a physician. Periodicity was once a year in 35% of cases, once every two years in 38%, and every 2-4 years in the remaining 27 %. Mammographies were performed at the Public Heath Service in 58 % of cases. The Public Health Service shows the highest percentage (42 %) of biennial periodicity. The variables more strongly associated with the use of screening mammography (probabilities 4 times higher) were: visit to a gynecologist and performance of a pap smear. Also related to the utilization of screening mammography were: personal history of breast pathology, family history of breast cancer, breast self-examination, and recent visit to a general practitioner. Self-perceived health presented an inverse relation with screening mammography use.Finally, the third study is a randomized controlled trial where three different strategies of inviting 50 to 64 years old women to participate in the program were compared. The strategy of direct contact increased in a significant way, up to 22%, the possibility of response after the first citation among women invited in the Raval Nord quarter. The response rate in the direct contact group was 62%, compared to 55% when the letter was sent by Primary Health Care Team, and 52% when it was sent by those responsible of the program. This increase in the direct contact group is noticeable even though only in 45 % of cases it was possible to contact the subject herself. When this was achieved, response raised to 72%. Use of non-health professionals to advise women seems to be an effective strategy, especially among women with a lower educational level.
46

Investigation of physical image characteristics and phenomenon of edge enhancement by phase contrast using equipment typical for mammography

Yamazaki, Asumi, Ichikawa, Katsuhiro, Kodera, Yoshie 23 October 2008 (has links)
No description available.
47

Evaluation of a Dedicated SPECT-CT Mammotomography System for Quantitative Hybrid Breast Imaging

Cutler, Spencer Johnson January 2010 (has links)
<p>The overall goal of this dissertation is to optimize and evaluate the performance of the single photon emission computed tomography (SPECT) subsystem of a dedicated three-dimensional (3D) dual-modality breast imaging system for enhanced semi-automated, quantitative clinical imaging. This novel hybrid imaging system combines functional or molecular information obtained with a SPECT subsystem with high-resolution anatomical imaging obtained with a low dose x-ray Computed Tomography (CT) subsystem. In this new breast imaging paradigm, coined "mammotomography," the subject is imaged lying prone while the individual subsystems sweep 3-dimensionally about her uncompressed, pendant breast, providing patient comfort compared to traditional compression-based imaging modalities along with high fidelity and information rich images for the clinician. </p><p> System evaluation includes a direct comparison between dedicated 3D SPECT and dedicated 2D scintimammography imaging using the same high performance, semi-conductor gamma camera. Due to the greater positioning flexibility of the SPECT system gantry, under a wide range of measurement conditions, statistically significantly (p<0.05) more lesions and smaller lesion sizes were detected with dedicated breast SPECT than with compressed breast scintimammography. The importance of good energy resolution for uncompressed SPECT breast imaging was also investigated. Results clearly illustrate both visual and quantitative differences between the various energy windows, with energy windows slightly wider than the system resolution having the best image contrast and quality.</p><p> An observer-based contrast-detail study was performed in an effort to evaluate the limits of object detectability under various imaging conditions. The smallest object detail was observed using a 45-degree tilted trajectory acquisition. The complex 3D projected sine wave acquisition, however, had the most consistent combined intra and inter-observer results, making it potentially the best imaging approach for consistent clinical imaging.</p><p> Automatic ROR contouring is implemented using a dual-layer light curtain design, ensuring that an arbitrarily shaped breast is within ~1 cm of the camera face, but no closer than 0.5 cm at every projection angle of a scan. Autocontouring enables simplified routine scanning using complex 3D trajectories, and yields improved image quality. Absolute quantification capabilities are also integrated into the SPECT system, allowing the calculation of in vivo total lesion activity. Initial feasibility studies in controlled low noise experiments show promising results with total activity agreement within 10% of the dose calibrator values.</p><p> The SPECT system is integrated with a CT scanner for added diagnostic power. Initial human subject studies demonstrate the clinical potential of the hybrid SPECT-CT breast imaging system. The reconstructed SPECT-CT images illustrate the power of fusing functional SPECT information to localize lesions not easily seen in the anatomical CT images. Enhanced quantitative 3D SPECT-CT breast imaging, now with the ability to dynamically contour any sized breast, has high potential to improve detection, diagnosis, and characterization of breast cancer in upcoming larger-scale clinical testing.</p> / Dissertation
48

A Biopsychosocial Study of the Mammography Pain Experiences of Breast Cancer Survivors

Scipio, Cindy Dawn January 2009 (has links)
<p>Based on a biopsychosocial model of mammography pain, the current study assessed if specific biological and psychosocial factors were associated with higher reported mammography pain in early stage breast cancer survivors. One hundred and twenty-seven women completed questionnaires assessing demographic information, cancer treatment history, ongoing breast pain, mammography-related anxiety, and social support immediately prior to receiving a mammogram. They then completed questionnaires assessing mammography pain and mammography-related pain catastrophizing immediately following the mammogram. Using path modeling and mediation analyses, relations among these variables were examined. Results revealed that mammography-related pain catastrophizing was related to higher mammography pain directly, while ongoing breast pain, lower social support quantity, and lower perceived quality of social support related to higher mammography pain indirectly through mammography-related pain catastrophizing. Moderated mediation analyses found that the mediation effects of mammography-related pain catastrophizing were significantly different at varying levels of perceived quality of social support, with more pronounced negative effects for those with higher quality support than those with lower quality support. The theoretical, clinical, and research implications of these findings are discussed.</p> / Dissertation
49

Economics of breast cancer preventive strategies in a Medicaid program

Borker, Rohit D. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains x, 158 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 133-145).
50

Perceived barriers to breast cancer screening: A comparison of African American and Caucasian women

Bastien, Natalie E 01 June 2005 (has links)
Although the incidence of breast cancer is high among Caucasian women, African American women continue to experience higher breast cancer mortality and lower survival rate in comparison to Caucasian women of the same age. Research regarding breast cancer screening among ethnic minority women from lower socioeconomic groups is extensive, but there is a lack of research that investigates barriers to breast cancer screening among African American women of higher socioeconomic status. The purpose of this study was to compare health beliefs of African American and Caucasian women regarding perceived barriers to breast cancer screening. The sample for this study consisted of 80 women, 40 African American and 40 Caucasian women, who were between the ages 40 to 80 years. The study was conducted at two local community churches located in Tampa, Florida. The barriers subscale from the Health Belief scale was used for data collection. Descriptive statistics were used to analyze demographic data, and independent t-test were used to compare the two groups in their perceived barriers. Results revealed that both groups perceived barriers to breast cancer, there were more similarities than differences. However, African American women were significantly more likely to indicate that having a mammogram would make them worry about breast cancer (p= 0.39). Although previous research has shown differences African American and Caucasian women, this study did not support those results. The two groups of women were similar in age, education, and marital status and all were active in their churches. Perhaps these similarities led to the lack of differences in perceived barriers scores between the two groups. This finding lends support to the idea that socioeconomic status more than race leads to disparities in breast screening.

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