Dissertationen zum Thema „CBCT technology“

Oral Biology
M.S.
Three dimensional imaging in the form of Cone Beam Computed Tomography has become prevalent in the field of orthodontics. Analytical methods of resulting volumetric data sets have not kept pace with the technology capable of producing them. Current 3D analysis techniques are largely adaptations of existing 2D methods, offering no clear diagnostic advantage over traditional imaging techniques in light of increased radiation exposure, and cannot be compared with norms generated from 2D image capture sources. In order to study morphology in 3D, data sets must be generated for longitudinal studies and native 3D analytical methods must also be developed. Existing methods of CBCT volume superimposition are cumbersome, involving complex software pipelines and multiple systems to complete the process. The goal of the current study was to develop a reproducible method of CBCT volume superimposition in the posterior cranial base in a single software package, and construct an easy to follow, step-by-step manual to facilitate future studies in craniofacial morphology. Existing anonymized sequential CBCT volumes of three subjects meeting inclusion criteria were obtained from the Kornberg School of Dentistry Department of Radiology. Volumes for each subject were imported into AMIRA software, resampled to a standardized 0.5 mm voxel size and superimposed with a mutual information algorithm. Posterior cranial base surface data was extracted using a semi-automatic technique. Resulting surface distance data was compiled and visualized through application of color maps. A streamlined image processing protocol was produced and documented in a detailed step-by-step manual. Surface distance analysis of serial segmentations was performed to verify reliability of the process. Surface distance deviations greater than 0.5 mm consistently fell below 0.2 percent of the total surface area. Sequential scan superimpositions of all three subjects exhibited mean surface distances of less than 0.15 mm. Two out of three subjects exhibited deviations of greater than 0.5 mm in less than 1 percent of the total surface area, suggesting consistent sub-voxel accuracy of the protocol.
Temple University--Theses

The topic of this thesis is the design of dental X-ray. User problems were identified based on the design and technical analysis for which solutions are presented in the work. The innovative shape and design solution shows a new approach to dental X-rays. The main benefit of the design is the solution to real ergonomic problems that can occur during the interaction of the operator or patient and the device. The design corresponds to current trends in the evolving design field of medical design.

L'imagerie est maintenant partie intégrante des traitements de radiothérapie. Avec la technologie CBCT embarquée sur les appareils de traitement, l'imagerie tomographique permet non seulement de repositionner fidèlement le patient tout au long de son traitement mais aussi d'adapter la planification initiale aux modifications quotidiennes de volume. C'est la radiothérapie adaptative, objet des travaux de cette thèse. Nous avons établi les limites techniques de précision de repositionnement des équipements utilisé. Ensuite, à partir des acquisitions CBCT quotidiennes de patients traités pour la prostate, nous avons élaboré une stratégie de traitement basée sur une banque de plans personnalisés. Nous avons mis au point une méthode semi-automatique de sélection du plan de traitement du jour qui a montré une efficacité supérieure à la sélection par des opérateurs expérimentés. Enfin, nous avons quantifié les doses additionnelles à la dose thérapeutique associées à l'utilisation quotidienne de l'imagerie CBCT. En conclusion, on peut dire qu'avec l'imagerie CBCT embarquée, on peut voir ce que l'on veut traiter, irradier ce que l'on a vu et contrôler ce qu'on a traité
Imaging is now fully integrated in the radiation therapy process. With on-board CBCT systems, tomography imaging allows not only patient positioning but also treatment planning adaptation with patient anatomy modifications, throughout the entire treatment. This is called adaptive radiation therapy, and is the main subject of this PhD thesis. During this work, we measured the repositioning accuracy of the system used. We also developed a treatment strategy using daily CBCT images and a personalized plan database to adapt treatment plan to patient anatomy. We found a way to select the daily treatment plan that shows superiority over operator selection. Then we also quantified the additional dose delivered while using this technique and the impact with regards to the risks added to patients. As a conclusion, with CBCT imaging, radiation therapy has entered an era where one can see what need to be treated, can treat what has been seen and can control what has been treated

Les images acquises par tomographie volumique à faisceaux coniques (CBCT) sont plus précises que celles de la radiologie classique tout en produisant 1.5 à 12 fois moins de rayons X. Ces bonnes précisions en font un outil intéressant ce qui concerne le diagnostic et la planification d’interventions chirurgicales. Ce n'est que récemment que son usage est entré dans la pratique pour des chirurgies lourdes, avec l'introduction de systèmes d'imagerie par radiographie dédiés, coûteux et encombrants. Une idée pour généraliser son utilisation à des chirurgies mineures, en orthopédie ou en traumatologie par exemple, serait de l’implanter sur le dispositif d’imagerie radiologique médicale le plus répandu en salle d’opération : l’arceau chirurgical mobile (C-arm).Cependant, le C-arm est incompatible avec les algorithmes de tomographie volumique de l’état de l’art qui nécessitent une connaissance très précise de la géométrie de l'image. En effet, un C-arm est mécaniquement instable et ses trajectoires sont non répétables. De plus, les algorithmes de calibration géométrique du C-arm mobile de l’état de l’art ne répondent pas aux exigences de cet usage : invasivité, modification trop importante de la routine chirurgicale, précision de localisation insuffisante… Dès lors, nous avons mis en évidence l’intérêt d’implanter une nouvelle méthode de calibration en ligne non invasive du C-arm. Pour ce faire, nous avons choisi d’exploiter principalement des mesures issues de capteurs inertiels.Pour répondre à cette problématique, nous abordons deux points : La construction d’un algorithme de calibration : l’idée est d’estimer la position et l’orientation du couple source-détecteur du C-arm mobile à partir des mesures inertielles et de modèles cinématiques adaptés, et grâce à des estimateurs (filtres et lisseurs de Kalman) correctement paramétrés. La propagation des erreurs d’estimation de positions et d’orientations jusqu’aux projetés 2D puis jusqu’aux reconstructions 3D : le but est d’évaluer l’impact des erreurs de localisation sur la qualité de reconstruction tout en permettant de déterminer les paramètres les plus impactants.Afin de valider le dispositif de calibration proposé, deux plateformes expérimentales ont été construites dans le cadre cette thèse : un bras rotatif qui permet de reproduire les mouvements de la source à rayons X ou du détecteur du C-arm dans le cas de trajectoires simplifiées, motorisées et répétables, et un C-arm réel qui a été sécurisé et motorisé, puis équipé de capteurs. Ce dernier nous a permis d’estimer la précision de localisation du couple source-détecteur pour des trajectoires réalistes.Sur une trajectoire classique d’un système réel, les erreurs maximales de calibration obtenues sont de l’ordre de 2 mm pour les positions et du dixième de degré pour les rotations. Ces résultats sont comparables à ceux obtenus par les méthodes de calibration invasives de l’état de l’art. La qualité de reconstruction a été évaluée sur des projetés 2D sur le plan détecteur puis sur des coupes de reconstructions 3D de mires et de fantômes réels. La précision sur l’orientation obtenue est évaluée comme étant suffisante pour garantir une bonne qualité de reconstruction. La précision sur la position est cependant jugée insuffisante. Néanmoins, les reconstructions obtenues, bien que visuellement déformées, gagneraient à être présentées et évaluées par un spécialiste médical. Les algorithmes de propagation d’erreurs ont également permis de conclure qu’une erreur sur les translations dans le plan de la source et du détecteur du C-arm ont, au moins, 6 fois plus d’impact sur les reconstructions que des erreurs sur les autres paramètres géométriques du C-arm
Cone beam computed tomography (CBCT) is more accurate than conventional radiography with less radiation exposure doses. Hence, it is a very useful complementary tool for diagnosis and surgery planning. Despite the increasing popularity of CBCT, it is mainly restricted to major surgery as it requires the use of expensive and bulky angiography systems which are specially designed to allow 3D tomography. One idea to generalize the use of CBCT to minor surgery - in orthopedics and traumatology for example - would be to introduce it on the most widely used tool for X-ray imaging: the mobile C-arm.Volume reconstruction algorithms require a very precise knowledge of the imaging geometry. Unfortunately, due to mechanical instabilities which lead to non-reproducible motions from run to run mobile C-arms are incompatible with existing tomography algorithms. Therefore, a precise C-arm on-line calibration is essential in order to achieve an accurate volume reconstruction. Existing calibration techniques do not meet these specifications. They are either not precise enough, invasive or involve a major change in the process of performing surgical acts. Therefore, we present a new on-line calibration method for mobile C-arms in order to achieve CBCT. It is based on tracking the detector and the X-ray source of the C-arm and aims to be precise and non-invasive.In order to address this issue, we will discuss two items: The first is the construction of a calibration algorithm: the idea is to estimate the position and the orientation of the detector and the X-ray source of the C-arm using inertial measurements, appropriate kinematic models, and a fitting estimator (Kalman filter and smoother). The second item is the propagation of pose estimation errors to 2D projections and to 3D reconstructions. Thus, we can evaluate the impact of the estimation errors on the reconstruction quality.This thesis also describes two experimental setups which allowed us to test and validate the proposed calibration algorithm. The first tracking experiments were carried out on a rotated-arm. It is a simple motorized mock-up to simulate either the detector or the X-ray source of a mobile C-arm. The rotated-arm exhibits a good position and orientation repeatability. The second platform is a full-size modified mobile C-arm. It includes motorized orbital and axial rotations, mechanical end stops and sensors of different characteristics and accuracies. This second platform allows us to estimate the geometric calibration accuracy on realistic trajectories.During a continuous rotation of the experimental C-arm, we achieve a tracking error of 2 mm for positions and of 0.1° for orientation. These values are comparable with existing invasive calibration algorithms accuracies. The image quality of reconstructed CBCT using the proposed calibration algorithm was evaluated on the 2D projections within the detector plane and also on the 3D reconstruction images of various phantoms. The achieved orientation accuracy is sufficient for CBCT. The position accuracy seems not. However, it may be useful to present the resulting 3D reconstruction images to medical evaluation by a specialist to confirm these conclusions. It also appears that the parameters of C-arm's projective geometry which have the greatest impact on the 2D projections are the in-plane translations of the X-ray source and of the detector. Therefore, they are the most critical parameters to be efficiently tracked in order to avoid artifacts in the 3D volume reconstruction. Compared to in-plane translations, the out-plane translations and the orientation of the detector have little influence on the 2D projections

The aim of this study is to investigate the effect of Bank employees&rsquo
individual and organization related individual differences on the acceptance of Learning Management System (LMS) in Central Bank of the Republic of Turkey (CBRT). The study aims to find out whether there are differences in perceived ease of use of technology, perceived usefulness of technology, and attitudes toward the use of LMS in terms of Bank employees&rsquo
gender, age, seniority, title, department, and LMS role groups. Survey design was used in this thesis study. Two self-report questionnaires were developed on LMS acceptance for two different LMS role groups. Accordingly, these questionnaires were distributed to department managers, training experts, training researchers, office staff and participants of training programs who have experienced LMS recently in the CBRT. 167 participants, and 64 department managers and office users responded the survey significantly. The data gathered via questionnaires was analyzed with the SPSS program, using descriptive and inferential statistics where correlation analysis and ANOVA were conducted. The results of the study showed that age and seniority of &ldquo
participants&rdquo
affect the participants&rsquo
acceptance of LMS
in particular they affect the perceived usefulness of LMS. Furthermore, the department of &ldquo
department managers and office users&rdquo
affects their acceptance of LMS regarding perceived usefulness, perceived ease of use, and attitudes toward the use of LMS. Consequently, the results of this case study can contribute to the literature regarding the determinants of technology acceptance factors.

Smoking has become one of the major global health concerns. Though there are various awareness activities being undertaken, the prevalence of smoking across the world is increasing at alarming levels. However, the extent of this increase varies among different countries. Even in culturally rich countries where smoking is considered as antagonistic behaviour both religiously and culturally, like Saudi Arabia, the prevalence of smoking is increasing at alarming levels. As smoking is mostly a behavioural aspect bundled with other factors, CBT (Cognitive Behavioural Therapy) integrated with m-health technologies represents a good strategy towards smoking cessation. This study focuses on developing a mobile smoking cessation management system - SMOKE MIND - using CBT intervention, and assessing its impact on achieving smoking cessation. This study uses mixed methods approach, where different methods are used at different stages of the research. Based on the systematic reviews and other literature reviewed, a questionnaire-based survey is conducted to assess the requirements of smokers in Saudi Arabia regarding the system for smoking cessation. The system developed uses CO readings of smokers, entered daily by participants through the mobile application, and assesses their improvement. Additionally, smokers enter CBT data if their CO readings are high, also through the mobile application. Based on these readings and CBT data, physicians recommend various activities and send motivational messages. The system is trailed for four weeks with an intervention group, who had access to the system, and a control group who did not. At the end of the study, another survey is conducted for evaluating the usability aspects of the SMOKE MIND system. The results achieved at the end of the study in evaluating the SMOKE MIND System reflect significant improvements in the participants in quitting smoking, and high satisfaction levels of the participants using the system. The values of p in both one-talied (0.0061) and two tailed (0.01) t-test are < 0.05, indicating that results are significant. 81.8% of the participants in intervention group and 40% participants in the control group quit smoking at the end of the study. A majority of the participants were highly satisfied with the various features used in the SMOKE MIND System.

Information Communication Technologies (ICT) are taking pace with rapid development,with the strive to impart education among learners in a way that they become highly satisfied.With a help of different electronic tools in educational technology using media and makingright environments to enhance learning, develop creativity, stimulate communication, createchannels for collaboration, and hence, engaging in the continued development and applicationto knowledge and skills. Usage of technology spans across all academic areas with theincreasing popularity of information technology that is evolving rapidly towards bettermentwith increased capabilities every day. Educationalists are interested in knowing howtechnology would create a variation for the students in the classroom. The purpose of using ELearningis to create a learning platform with combination of the existing knowledge andInformation Communication Technologies (ICT). High growth in Information Technology thatis user friendly, accessible, and reliable at the same time providing improved ways incollaborating in a new approach possible. Students from different units would be able tocollaborate forming cross-unit teams and working on common or multiple assignmentshelping each other in different ways. Internet, video conferencing, and emails are wellestablished collaborative tools for exchange of information. Investigating that why there is aneed of technology in the education and which technologies would help in improving learningprocesses is the main purpose of this research. And also to find that what would be thenecessary infrastructure required to get facilitated by this technology. The research revolvesaround the theory of Computer Based Training (CBT) which refers to particular part of theinstructional development or educational media.
Program: Magisterutbildning i informatik

South Africa since the liberation in 1994 has faced a lot of changes. The changes include being a member of the international community. As part of the international community, South Africa is finding itself largely faced by the challenges associated with this position. Looking at other countries South Africa is realizing that the world is looking at better ways of educating their people and organizing their education and training systems so that they might gain the edge in an increasingly competitive economic global environment. Success and survival in such a world demands that South Africa has a national education and training system that provides quality learning and promotes the development of a nation that is committed to life-long learning. Institutions of higher education in South Africa are currently changing their present education system to conform to a Competency-Based Training (CBT) system. This system has only been planned but not implemented yet and it is not clear how CBT will be implemented, especially how the learners are going to be assessed. Competency-Based Assessment (CBA) is an integral part of CBT that needs particular attention if the new system is to succeed. The key aims of this thesis are to investigate the current assessment policy and practice at the Canberra Institute of Technology (CIT) underpinned by Competency- Based Training system. The project will describe and analyze the Competency-Based Assessment system used within CIT's CBT system. The project will focus on: Observing classroom practice of CBA, analyzing students' and teachers' perceptions of their involvement with CBA, and analyzing employers' perceptions of the effectiveness of CBA. The main aim of this thesis is to suggest recommendations for an assessment model that will be suitable to implement within hospitality training institutions in South Africa.

Magistro darbe analizuojamas informacinių technologijų taikymas Lietuvos logopedų darbe. Apie IKT ir KMP taikymą Lietuvos logopedų darbe nėra daug žinoma, nėra parengta išsamių mokslinių straipsnių ar apžvalgų, kurie nurodytų, kokiomis informacinių technologijų programomis ar priemonėmis naudojamasi logopedų darbe, kokios iš jų vyrauja ir kurios yra efektyviausios dirbant su kalbos, kalbėjimo ir komunikacijos sutrikimų turinčiais asmenimis. Praktinis tyrimo naudingumas – atskleisti informacinių technologijų taikymo realybę logopedų darbe su kalbėjimo ir kalbos sutrikimų turinčiais asmenimis. Palyginti pasiekimus šioje srityje Lietuvoje ir užsienio šalyse. Prieduose pateikiamas internetinių svetainių sąrašas, kur galima rasti logopedinėse pratybose pritaikomų lavinimo užduočių.
Master’s thesis analyzes the informational technologies application in Lithuanian speech and language therapists’ work. The aim of this research - to assess the informational and communication technology (ICTs) and computer-based speech training system (CBST) use at the speech and language therapists work in comprehensive schools who work with persons who have language, speech and communication disorders. The empirical part of the paper deals with the use of ICTs/ CBST at speech and language therapists work, their possibility of usage, the coherence between speech therapists qualification and their age, the usage of the programs for development educable self-dependent tools, speech and language therapists interest in various sources of work-related topics and others. In the questionnaire survey (in electronic form) have participated 258 speech and language therapists who work in comprehensive schools.

Inom nätverksbranchen finns en strävan att gå från proprietära lösningar till en öppen standard för hård- och mjukvara. En term för detta är Whiteboxing och det innebär att användaren ges möjlighet att plocka ihop komponenter efter behov, och själv välja vilken mjukvara som används. I sin enklaste form byggs en Whiteboxrouter av en konventionell PC med två nätverkskort och en mjukvarubaserad routingapplikation. Företaget ÅF är intresserade av att veta hur Whitebox-lösningar för routrar står sig prestandamässigt i relation till konventionella routerlösningar med Application Specific Integrated Circuit. Detta arbete har undersökt prestandan genom att mäta throughput och goodput hos en Cisco 2911-router, en Whiteboxrouter med mjukvaran pfSense, samt en Whiteboxrouter som körde pfSense virtualiserat på ESXi. Dessutom undersöktes respektive konfigurations prestanda när trafiken skickades över IPsec VPN. För mätningarna användes filöverföringar med FTP och mätprogrammet Iperf3. Målet med arbetet var att skapa ett beslutsunderlag som klargjorde eventuella prestandaskillnader och utarbetade rekommendationer för framtida val av routerlösning. Resultatet visade att vid generell paketförmedling var prestandan mellan routrarna relativt jämn, dock rekommenderas den virtualiserade Whiteboxroutern då den fick det bästa resultatet. När trafiken sedan krypterades med IPsec VPN var det stora prestandaskillnader mellan enheterna. Bäst prestanda fick Whiteboxroutern. Författaren ser en vinning med Whitebox-tekniken i stort då den medger att serverutrustning som ska utrangeras på grund av prestandakrav, istället kan fungera som nätverksutrustning (routrar och brandväggar) och fortsätta användas under en större del av den tekniska livslängden. Detta kan på sikt leda till minskad miljöpåverkan och besparingar för företaget.

This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.

This thesis applies a sociological framework to the North American celebrity career of Canadian pianist and broadcaster Glenn Gould (1932-1982) to account for Gould's iconic status as an artist in modern musical culture. Despite the persistent cultural fascination with Gould, as evidenced in the seemingly endless supply of biographies, films, novels, and fan texts which narrate and celebrate his life and work, modern Gould scholarship has consistently neglected issues relating to his artistic reception. This thesis proposes that the modern Gould phenomenon is productively analysed in terms of the contexts of its historical production in North America, where it first originated. Focusing on the circumstances of Gould's career during his lifetime, it identifies three areas of overlapping conceptual interest that provide the basis for an explanatory account of his modern mythology: i) Gould's relationship to the culture of his time, particularly in Canada; ii) Gould's relationship to the mass media; iii) Gould's relationship to his own artistic identity. This approach is refined through the application of Stuart Hall's 'Circuit of Culture' model, which yields an understanding of Gould's celebrity in terms of the processes of its representation, production, regulation, and consumption. Against this theoretical backdrop, and consistent with the premise of my thesis, I ask some key questions: what was Gould's relationship to Canadian cultural nationalism and, specifically, a nationalist discourse of public broadcasting? How did media institutions brand his image, and for what commercial purposes? How did Gould mobilise understandings of his genius and Canadian identity through his artistic discourse and experimental media self-representations as a 'Northerner' and a technologist? Based on this analysis, the thesis concludes that Gould continues to fascinate because of the unique ideological work performed by his cultural identities, and because of the highly mediated nature of his celebrity. The ubiquity of his image on video-sharing websites and social media platforms is a vindication of his radical belief in the validity of a musical career pursued primarily through the electronic media.

This qualitative study uses narrative inquiry (Connelly & Clandinin, 1988, 1990, 2001) and self-study to investigate ways to further understand and facilitate the integration of holistic philosophies of education with media literacy pedagogies. As founder and director of the Youth Media Literacy Project and a self-titled Imagitator (one who agitates imagination), I have spent over 10 years teaching media literacy in various high schools, universities, and community centres across North America. This study will focus on my own personal practical knowledge (Connelly & Clandinin, 1982) as a culture jammer, educator and cancer survivor to illustrate my original vision of a ‘holistic media literacy pedagogy’. This research reflects on the emergence and impact of holistic media literacy in my personal and professional life and also draws from relevant interdisciplinary literature to challenge and synthesize current insights and theories of media literacy, holistic education and culture jamming.