<p>Fluoroskopi är benämningen på kontinuerlig röntgengenomlysning av en patient. Eftersom patienten och även läkaren då utsätts för kontinuerlig röntgenstrålning måste strålningsdosen hållas låg, vilket leder till brusiga bilder. Det är därför önskvärt att genom bildbehandling förbättra bilderna. Bildförbättringen måste dock ske i realtid och därför kan inte konventionella metoder användas.</p><p>Detta examensarbete avser att undersöka hur ortogonala s k. derivataoperatorer kan användas för att förbättra läsbarheten av fluoroskopibilder med hjälp av brusundertryckning och kantförstärkning. Derivataoperatorer är separerbara vilket gör dem extremt beräkningsvänliga och lätta att infoga i en skalpyramid. Skalpyramiden ger möjlighet att processa strukturer och detaljer av olika storlek var för sig samtidigt som nedsamplingsmekanismen gör att denna uppdelning inte nämnvärt ökar beräkningsbördan. I den fullständiga lösningen införes också struktur-/brusseparering för att förhindra förstärkning av och undertrycka bidrag från de frekvensband där en pixel domineras av brus.</p><p>Resultaten visar att brus verkligen kan undertryckas medan kanter och linjer bevaras bra eller förstärkes om så önskas. Den riktade filtreringen gör dock att det lätt uppstår maskliknande strukturer i bruset, men detta kan undvikas med rätt parameterinställning av struktur-/brussepareringen. Förhållandet mellan riktad och icke-riktad filtrering är likaledes styrbart via en parameter som kan optimeras med hänsyn till behov och önskemål vid varje tillämpning.</p> / <p>In X-ray technology, fluoroscopy stands for continuous irradiation. For the sake of both patients and doctors the dose has to be kept low, which leads to noisy images and the question of possible enhancement by digital image processing. Since such enhancement has to be done in real-time, most conventional and available methods are unsuitable.</p><p>The purpose of this thesis is to examine how derivative operators can be used to improve fluoroscopy images in terms of noise reduction and edge enhancement. Since the derivative operators are designed as highly separable convolution kernels the image derivatives can be computed very efficiently with a scheme that is readily embedded in a scale-space pyramid. In this pyramid, structures and details of different sizes can be processed separately with optimal parameter settings. In the final solution we also discriminate between structure and noise in order to avoid amplification, even suppress contributions from frequency bands where a certain pixel position is dominated by noise.</p><p>Experimental results show that noise can indeed be suppressed while edges and lines are enhanced. Oriented filtering may induce false structures in areas where only noise is present, something that can be avoided by correcting the parameters in the noise/structure discriminator. The relation between oriented and non-oriented filtering is likewise controllable with a parameter that can be optimized for application dependent needs and desires.</p>

Abstract Fluoroscopically guided procedures are currently an area of special concern in relation to radiation protection, as they may produce a high radiation dose to patients and increase the risk of skin injury. ERCP is a gastrointestinal procedure used as a gold standard in the treatment of pancreatobiliary disorders. It is performed under endoscopic and fluoroscopic guidance. Recently, both the number and the complexity with associated increased technical difficulty of therapeutic ERCP procedures have significantly increased. The present study aimed to assess the medical use of radiation in ERCP, with special emphasis on optimisation of radiation protection of patients. For this purpose, the level of patient radiation exposure during ERCP was evaluated by registering the radiation dose indices in Finnish hospitals. The entrance surface dose was measured by thermoluminescent dosimeters and the effective dose was estimated using conversion coefficients. For dose optimisation and for quality assurance, the local diagnostic reference levels (DRL) for ERCP were established and reviewed after five years. A single centre prospective analysis was conducted to identify patient-, procedure- and operator-related factors affecting dose area product (DAP) and fluoroscopy time (FT). The results showed a large variation of dose indices in overall, as among participating hospitals due to differences in patient characteristics, operator, equipment and procedural complexity. The risk of radiation-induced skin injury and the lifetime cancer risk seems to be reasonably low, indicating ERCP to be a low-dose study. Local DRL is an effective tool in the optimisation process, as a certain degree of dose reduction was achieved during the years. Multiple factors were found to affect DAP and FT in ERCP. The awareness of these factors may help to predict possible prolonged procedures that cause a higher radiation dose to the patient and thus facilitate the use of appropriate precautions. / Tiivistelmä Säteilysuojelun näkökulmasta läpivalaisuohjauksessa tehtävät toimenpiteet ovat erityisen huolen aiheena, koska ne voivat aiheuttaa potilaille suuria säteilyannoksia ja siten lisätä ihovaurion riskiä. ERCP on ruoansulatuskanavan endoskopiatoimenpide, jota käytetään haima- ja sappitiesairauksien hoidossa kultaisena standardina. ERCP suoritetaan duodenoskoopilla läpivalaisukontrollissa. Viime vuosina ERCP toimenpiteiden määrät ja toimenpiteiden monimutkaisuus ovat kasvaneet merkittävästi lisääntyneen teknisen haastavuuden vuoksi. Tutkimuksen tarkoituksena oli arvioida säteilyn lääketieteellistä käyttöä ERCP:ssa, kiinnittäen eritystä huomiota potilaan säteilysuojelun optimointiin. Potilaan säteilyaltistuksen tasoa ERCP:ssa arvioitiin keräämällä potilasannoksia suomalaisista sairaaloista, pinta-annokset mitattiin termoloistedosimetreilla ja efektiivinen annos laskettiin muuntokertoimilla. Säteilyaltistuksen optimointi- ja laadunvalvonnan työkaluksi ERCP:lle asetettiin paikalliset vertailutasot ja ne tarkistettiin 5 vuoden kuluttua. Potilaaseen, toimenpiteeseen ja toimenpiteen suorittajaan liittyvät tekijät, jotka vaikuttavat annoksen ja pinta-alan tuloon (DAP) sekä läpivalaisuaikaan, selvitettiin retrospektiivisesti yhdessä sairaalassa. Tutkimuksen tulokset osoittivat, että potilaan säteilyannoksissa oli suurta vaihtelua niin yleisesti, kuin osallistuvien sairaaloiden välillä. Vaihtelu johtui potilaan ominaisuuksista, erilaisista läpivalaisulaitteista, toimenpiteen suorittajista ja ERCP toimenpiteiden vaikeusasteesta. Säteilyn aiheuttaman ihovaurion riski ja elinikäinen syöpäriski näyttäisi tulosten perusteella olevan kohtuullisen alhainen, mikä osoittaa, että ERCP on matala-annostutkimus. Paikallinen vertailutaso osoittautui tehokkaaksi optimointityökaluksi, sillä annostason lasku ERCP:ssa saavutettiin vuosien kuluessa. Useiden tekijöiden todettiin vaikuttavan DAP:n ja läpivalaisuaikaan ERCP:ssa. Näiden tekijöiden tiedostaminen voi auttaa tunnistamaan etukäteen ne haastavat ERCP toimenpiteet, jotka voivat aiheuttaa suuria säteilyannoksia potilaille, ja siten mahdollistaa niihin varautumisen.

A Radiologia tem sido considerada uma das áreas da Medicina que mais se desenvolve, especialmente com o aporte de novas tecnologias. Entre as aplicações da Radiologia Intervencionista destaca-se a utilização da fluoroscopia no centro cirúrgico em complemento às cirurgias ortopédicas, objeto da presente pesquisa. Entretanto, alguns complexos e longos procedimentos guiados fluoroscopicamente podem resultar em altos níveis de exposição ocupacional às radiações ionizantes para equipe de cirurgia ortopédica e trabalhadores de saúde, induzir sérios danos à saúde. Levando em conta esses aspectos, o objetivo geral dessa pesquisa consiste em determinar a exposição ocupacional da equipe de cirurgia ortopédica em procedimentos guiados por fluoroscopia e verificar dentre as cirurgias observadas a que oferece maior exposição ocupacional às radiações ionizantes, como também, a aplicação dos princípios básicos de proteção radiológica nestes procedimentos. A metodologia utilizada para essa pesquisa foi a qualiquantitativa do tipo exploratória. A pesquisa foi realizada no Hospital de Clínicas da Universidade Federal de Curitiba (UFPR). Os sujeitos pesquisados foram os membros da equipe de cirurgia ortopédica, ou seja, médicos ortopedistas, residentes, anestesias, instrumentador cirúrgico, técnicos e auxiliares de enfermagem, e enfermeiros. A coleta de dados foi realizada de 01 de janeiro a 30 de maio de 2011. Contribuíram para a pesquisa, 44 trabalhadores que responderam uma entrevista coletiva, e um questionário com 25 perguntas fechadas. foi constituídos quatro grupos de onze participantes cada, seguida de análise documental e de monitoração da área pesquisada e individual. Os resultados mostraram que os profissionais de saúde do setor pesquisado expõem-se às radiações ionizantes, devido à demanda de cirurgias guiadas por equipamentos emissores de radiação ionizantes fluoroscopicamente, e a falta de conhecimento em radioproteção. Diante dessas constatações foram sugeridas pelos grupos medidas de prevenção a essas exposições de modo a minimizar possíveis efeitos biológicos das radiações ionizantes. Foi concluído que existe exposição ocupacional com os trabalhadores do setor pesquisado, os mesmos tem pouco conhecimento quanto ao uso dos equipamentos de radioproteção nos procedimentos cirúrgicos com equipamentos emissores de radiações ionizantes, não usam corretamente os monitores individuais. / Radiology has been considered one of the areas of medicine that most devel-ops, especially with the contribution of new technologies. Among the applications of Interventional Radiology highlights the use of fluoroscopy in the surgical center in addition to co-orthopedic surgeries, the object of the present research. Entretan-to some complex and lengthy fluoroscopically guided procedures can result in high levels of occupational exposure to ionizing radiation for e-quipe orthopedic surgery and health workers, induce serious damage to health. Considering these aspects, the general objective of this research is to de-termine the occupational exposure of the team of orthopedic surgery proce-dures guided by fluoroscopy and verify observed among the surgeries that offer greater occupational exposure to ionizing radiation, but also the application of basic principles of radiological protection in these procedures. The methodology for this research was the qualitative and quantitative exploratory type. The research was conducted at Hospital de Clinicas, Federal University of Curitiba (UFPR). Study subjects were members of the team of orthopedic surgery, or orthopedic doctors, residents, anesthesia, surgical instrumentator, technicians and nursing assistants, and nurses. Data collection was performed from January 1 to May 30, 2011. Contributors to the survey, 44 workers who answered a news conference, and a questionnaire with 25 closed questions of. was divided in four groups of eleven participants each, followed by document analysis and monitoring of the area and searched individually. The results we-strated that the health sector professionals surveyed were exposed to ionizing radiation, due to demand-driven surgery equipment emitting ionizing radiation fluoroscopically, and the lack of knowledge in radioprote-tion. Before these findings were suggested by the groups pre-vention measures of these exposures to minimize possible biological effects of ionizing radiation-tions. It was concluded that occupational exposure exists with re-worked in the sector researched, they have little knowledge about the use of radiation protection equipment in surgical procedures with equipment emitting ionizing radiation, properly use the monitors indi-tions.

A Radiologia tem sido considerada uma das áreas da Medicina que mais se desenvolve, especialmente com o aporte de novas tecnologias. Entre as aplicações da Radiologia Intervencionista destaca-se a utilização da fluoroscopia no centro cirúrgico em complemento às cirurgias ortopédicas, objeto da presente pesquisa. Entretanto, alguns complexos e longos procedimentos guiados fluoroscopicamente podem resultar em altos níveis de exposição ocupacional às radiações ionizantes para equipe de cirurgia ortopédica e trabalhadores de saúde, induzir sérios danos à saúde. Levando em conta esses aspectos, o objetivo geral dessa pesquisa consiste em determinar a exposição ocupacional da equipe de cirurgia ortopédica em procedimentos guiados por fluoroscopia e verificar dentre as cirurgias observadas a que oferece maior exposição ocupacional às radiações ionizantes, como também, a aplicação dos princípios básicos de proteção radiológica nestes procedimentos. A metodologia utilizada para essa pesquisa foi a qualiquantitativa do tipo exploratória. A pesquisa foi realizada no Hospital de Clínicas da Universidade Federal de Curitiba (UFPR). Os sujeitos pesquisados foram os membros da equipe de cirurgia ortopédica, ou seja, médicos ortopedistas, residentes, anestesias, instrumentador cirúrgico, técnicos e auxiliares de enfermagem, e enfermeiros. A coleta de dados foi realizada de 01 de janeiro a 30 de maio de 2011. Contribuíram para a pesquisa, 44 trabalhadores que responderam uma entrevista coletiva, e um questionário com 25 perguntas fechadas. foi constituídos quatro grupos de onze participantes cada, seguida de análise documental e de monitoração da área pesquisada e individual. Os resultados mostraram que os profissionais de saúde do setor pesquisado expõem-se às radiações ionizantes, devido à demanda de cirurgias guiadas por equipamentos emissores de radiação ionizantes fluoroscopicamente, e a falta de conhecimento em radioproteção. Diante dessas constatações foram sugeridas pelos grupos medidas de prevenção a essas exposições de modo a minimizar possíveis efeitos biológicos das radiações ionizantes. Foi concluído que existe exposição ocupacional com os trabalhadores do setor pesquisado, os mesmos tem pouco conhecimento quanto ao uso dos equipamentos de radioproteção nos procedimentos cirúrgicos com equipamentos emissores de radiações ionizantes, não usam corretamente os monitores individuais. / Radiology has been considered one of the areas of medicine that most devel-ops, especially with the contribution of new technologies. Among the applications of Interventional Radiology highlights the use of fluoroscopy in the surgical center in addition to co-orthopedic surgeries, the object of the present research. Entretan-to some complex and lengthy fluoroscopically guided procedures can result in high levels of occupational exposure to ionizing radiation for e-quipe orthopedic surgery and health workers, induce serious damage to health. Considering these aspects, the general objective of this research is to de-termine the occupational exposure of the team of orthopedic surgery proce-dures guided by fluoroscopy and verify observed among the surgeries that offer greater occupational exposure to ionizing radiation, but also the application of basic principles of radiological protection in these procedures. The methodology for this research was the qualitative and quantitative exploratory type. The research was conducted at Hospital de Clinicas, Federal University of Curitiba (UFPR). Study subjects were members of the team of orthopedic surgery, or orthopedic doctors, residents, anesthesia, surgical instrumentator, technicians and nursing assistants, and nurses. Data collection was performed from January 1 to May 30, 2011. Contributors to the survey, 44 workers who answered a news conference, and a questionnaire with 25 closed questions of. was divided in four groups of eleven participants each, followed by document analysis and monitoring of the area and searched individually. The results we-strated that the health sector professionals surveyed were exposed to ionizing radiation, due to demand-driven surgery equipment emitting ionizing radiation fluoroscopically, and the lack of knowledge in radioprote-tion. Before these findings were suggested by the groups pre-vention measures of these exposures to minimize possible biological effects of ionizing radiation-tions. It was concluded that occupational exposure exists with re-worked in the sector researched, they have little knowledge about the use of radiation protection equipment in surgical procedures with equipment emitting ionizing radiation, properly use the monitors indi-tions.

Fluoroskopi är benämningen på kontinuerlig röntgengenomlysning av en patient. Eftersom patienten och även läkaren då utsätts för kontinuerlig röntgenstrålning måste strålningsdosen hållas låg, vilket leder till brusiga bilder. Det är därför önskvärt att genom bildbehandling förbättra bilderna. Bildförbättringen måste dock ske i realtid och därför kan inte konventionella metoder användas. Detta examensarbete avser att undersöka hur ortogonala s k. derivataoperatorer kan användas för att förbättra läsbarheten av fluoroskopibilder med hjälp av brusundertryckning och kantförstärkning. Derivataoperatorer är separerbara vilket gör dem extremt beräkningsvänliga och lätta att infoga i en skalpyramid. Skalpyramiden ger möjlighet att processa strukturer och detaljer av olika storlek var för sig samtidigt som nedsamplingsmekanismen gör att denna uppdelning inte nämnvärt ökar beräkningsbördan. I den fullständiga lösningen införes också struktur-/brusseparering för att förhindra förstärkning av och undertrycka bidrag från de frekvensband där en pixel domineras av brus. Resultaten visar att brus verkligen kan undertryckas medan kanter och linjer bevaras bra eller förstärkes om så önskas. Den riktade filtreringen gör dock att det lätt uppstår maskliknande strukturer i bruset, men detta kan undvikas med rätt parameterinställning av struktur-/brussepareringen. Förhållandet mellan riktad och icke-riktad filtrering är likaledes styrbart via en parameter som kan optimeras med hänsyn till behov och önskemål vid varje tillämpning. / In X-ray technology, fluoroscopy stands for continuous irradiation. For the sake of both patients and doctors the dose has to be kept low, which leads to noisy images and the question of possible enhancement by digital image processing. Since such enhancement has to be done in real-time, most conventional and available methods are unsuitable. The purpose of this thesis is to examine how derivative operators can be used to improve fluoroscopy images in terms of noise reduction and edge enhancement. Since the derivative operators are designed as highly separable convolution kernels the image derivatives can be computed very efficiently with a scheme that is readily embedded in a scale-space pyramid. In this pyramid, structures and details of different sizes can be processed separately with optimal parameter settings. In the final solution we also discriminate between structure and noise in order to avoid amplification, even suppress contributions from frequency bands where a certain pixel position is dominated by noise. Experimental results show that noise can indeed be suppressed while edges and lines are enhanced. Oriented filtering may induce false structures in areas where only noise is present, something that can be avoided by correcting the parameters in the noise/structure discriminator. The relation between oriented and non-oriented filtering is likewise controllable with a parameter that can be optimized for application dependent needs and desires.

No description available.

The aim of the thesis is to design and implement a simulator of image reconstruction during x-ray computed tomography fluoroscopy. Apart from quantitative evaluation of particular imaging process parameters influence, the intended program application will lie in optimization of these parameter values. Introductory part is focused on brief theoretical description of x-ray computed tomography imaging process. Emphasis is placed on fluoroscopy-specific approaches, particularly the division of scanned projections into chosen amount of sectors as well as fluoroscopic imaging process evaluation methods. The subsequent part deals with program implementation and its limitations and sketches the possible working framework. Moreover, one of the chapters is devoted to optimization of imaging process parameters measurement. The final part aims at impact analysis of particular process parameters as well as fluoroscopic imaging process optimization approaches. The thesis consists also of a didactic simulator enabling real-time intervention simulation with manual instrument manipulation. Since both simulators are intended for teaching purposes, the thesis is supplemented with a laboratory exercise draft.

[Truncated abstract] Measuring the kinematics of joints and implants following orthopaedic surgery is important since joint motion directly influences the functional outcome of the patient and the longevity of the implant. Radiostereometric Analysis (RSA) has been used to assess the motion over time of various joints and implant designs following corrective orthopaedic and joint replacement surgery for more than 20 years in more than 10,000 patients around the world. While the use of RSA reduces the risk of implanting potentially inferior prostheses on a large scale, conventional methodological procedures are based on the acquisition of static, stereographic x-ray images that are not suitable for measuring skeletal kinematics in a dynamic manner. The purpose of this thesis was to design, validate and test a novel technique for dynamically assessing the skeletal motion of human subjects using RSA and single-plane digital x-ray video fluoroscopy. The validation procedure utilised two in-vitro phantom models of human joints capable of simulating normal kinematic motion. These phantom models were supplied with realistic spatial displacement protocols derived from cadaveric specimens. The spatial positions of a series of tantalum markers that were implanted in each skeletal segment were measured using RSA. Skeletal motion was determined in x-ray fluoroscopy images by minimising the difference between the markers measured and projected in the single image plane. Accuracy was determined in terms of bias and precision by analysing the deviation between the applied displacement protocol and measured pose estimates. ... The RSA and low dose single-plane fluoroscopy technique developed, validated and tested in this thesis is capable of dynamically measuring the kinematics of any joint in the human body, following the implantation of small metallic markers in the surrounding bone during corrective orthopaedic surgery. The kinematics of joints with replacement prostheses, such as the total knee replacement (TKR), can be analysed in addition to the kinematics of joints without replacement prostheses, such as the sacroiliac joint. The technique may be used in the future on groups of human subjects enrolled in controlled trials that are designed to analyse the kinematics of the shoulder, spine, hip, knee, patella or ankle joints for the purposes of quantitatively comparing the kinematics of different prosthesis designs and various corrective orthopaedic procedures.

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).

Vu le caractère non-invasif des procédures d’électrophysiologie interventionnelle, la visualisation de régions anatomiques d'intérêt et une orientation adéquate en cours de procédure sont nécessaires. L'objectif de cette thèse est d'étudier, d'optimiser et d'étendre l’utilisation des modalités d'imagerie radiographique. La dose de radiation effective (ED) est calculée d’une façon spécifique au patient pour l’angiographie rotationnelle 3D (3DRA) et il est démontré qu'en ajustant l’acquisition en 3DRA et en fluoroscopie, une réduction de dose importante est possible sans compromettre la qualité d’image nécessaire à la procédure. Un protocole d'acquisition et post traitement pour obtenir une imagerie dynamique basée sur le 3DRA est présenté,permettant une réduction du bruit d'image et une segmentation d'images automatique. L'extraction d'informations dynamiques, structurelles et fonctionnelles à partir d'images MDCT, relatives à la gestion de la fibrillation auriculaire (FA) est étudiée. La fonction auriculaire globale est examinée et des cartes de mouvement régional et de tissu adipeux épicardique sont produites et liés à la FA à différents stades. Une méthode automatisée est présentée pour mesurer l’orifice de l’appendice auriculaire gauche au long du cycle cardiaque et pour optimiser le déploiement de dispositifs de fermeture. Optimiser l’usage des rayons X, les protocoles d'acquisition et les méthodes de post traitement d’images, permet d’obtenir des informations supplémentaires pertinentes aux procédures d'électrophysiologie interventionnelle depuis les modalités d'imagerie radiographiques sans compromettre la qualité d’image ou le flux de travail procédural. / Due to their non-invasive character, interventional electro physiological procedures require visualisation of anatomical regions of interest and adequate guidance of procedural manoeuvres. The aim of this thesis was to study, optimise and expand the use of radiographic imaging modalities. The first part focuses on the influence of C-arm system image acquisition parameters on radiation dose incurred by the patient. We developed a patient-specific way to calculate effective dose (ED) in 3Drotational angiography (3DRA) and showed in 3DRA and fluoroscopy that by applying adequate protocol adjustments, an important dose reduction could be obtained without compromising necessary image quality. The second part focuses on the development and validation of an acquisition and post-processing protocol for dynamic imaging using 3DRA. This method enables automatic image noise reduction and image segmentation. The third part focuses on the extraction of dynamic,structural and functional information from MDCT images, relevant to management of atrial fibrillation (AF). We studied atrial function and generated maps of regional atrial motion and epicardial adipose tissue and related them to AF burden. We also developed an automated method to measure LA appendage orifice dimensions through out the cardiac cycle to optimise measurements for deployment of closure devices.Overall we demonstrate that by optimising radiation usage, acquisition protocols and image post-processing methods, additional information relevant to interventional electrophysiological procedures can be extracted from radiographic imaging modalities without compromising image quality or procedural workflow.