Bakgrund: I magnetisk resonanstomografi (MR) är kontrastmedel baserat på gadolinium vanligast. Den senaste forskningen har visat att gadolinium kan lagras långvarigt i hjärnvävnad. Röntgensjuksköterskan administrerar vanligtvis kontrastmedlet till patienten vid undersökningen.  Syfte: Syftet är att belysa deponering av gadolinium i hjärnvävnaderna nucleus dentatus och globus pallidus efter administrering av gadoliniumbaserade kontrastmedel samt eventuella risker till följd av deponeringen. Metod: Litteraturstudien inkluderar 16 vetenskapliga artiklar varav den äldsta artikeln är från 2014. Sökningen av artiklarna gjordes via Jönköpings högskolebibliotek och har kvalitetsgranskats av författarna. Resultat: Deponering i hjärnvävnad kunde påvisas bland linjära gadoliniumbaserade kontrastmedel. Liknande mätning med makrocykliska kontrastmedel gav ej samstämmiga resultat. Risker av deponeringen kunde ej påvisas. Slutsats: En litteraturstudie som belyser deponeringsrisker kring användandet av gadoliniumbaserade kontrastmedel. Verksamma röntgensjuksköterskor bör ha kunskap om dessa deponeringsrisker vid administrering av gadoliniumbaserat kontrastmedel.

abstract: Computed tomography (CT) is one of the essential imaging modalities for medical diagnosis. Since its introduction in 1972, CT technology has been improved dramatically, especially in terms of its acquisition speed. However, the main principle of CT which consists in acquiring only density information has not changed at all until recently. Different materials may have the same CT number, which may lead to uncertainty or misdiagnosis. Dual-energy CT (DECT) was reintroduced recently to solve this problem by using the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between two low and high energy images or measurements, so that it is difficult to acquire the accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, a new model and an image enhancement technique for DECT are proposed, based on the fact that the attenuation of a high density material decreases more rapidly as X-ray energy increases. This fact has been previously ignored in most of DECT image enhancement techniques. The proposed technique consists of offset correction, spectral error correction, and adaptive noise suppression. It reduced noise, improved contrast effectively and showed better material differentiation in real patient images as well as phantom studies. / Dissertation/Thesis / Ph.D. Bioengineering 2011

abstract: Phase contrast magnetic resonance angiography (PCMRA) is a non-invasive imaging modality that is capable of producing quantitative vascular flow velocity information. The encoding of velocity information can significantly increase the imaging acquisition and reconstruction durations associated with this technique. The purpose of this work is to provide mechanisms for reducing the scan time of a 3D phase contrast exam, so that hemodynamic velocity data may be acquired robustly and with a high sensitivity. The methods developed in this work focus on the reduction of scan duration and reconstruction computation of a neurovascular PCMRA exam. The reductions in scan duration are made through a combination of advances in imaging and velocity encoding methods. The imaging improvements are explored using rapid 3D imaging techniques such as spiral projection imaging (SPI), Fermat looped orthogonally encoded trajectories (FLORET), stack of spirals and stack of cones trajectories. Scan durations are also shortened through the use and development of a novel parallel imaging technique called Pretty Easy Parallel Imaging (PEPI). Improvements in the computational efficiency of PEPI and in general MRI reconstruction are made in the area of sample density estimation and correction of 3D trajectories. A new method of velocity encoding is demonstrated to provide more efficient signal to noise ratio (SNR) gains than current state of the art methods. The proposed velocity encoding achieves improved SNR through the use of high gradient moments and by resolving phase aliasing through the use measurement geometry and non-linear constraints. / Dissertation/Thesis / Ph.D. Bioengineering 2011

Bakgrund: Prostatacancer diagnostiseras oftast med en prostatabiopsi ledd utav ett transrektalt ultraljud (TRUS). Magnetisk resonanstomografi kan också användas för att upptäcka prostatacancer och en diagnos kan sedan ställas utifrån bildtagningen. Vanligare är dock att MR används som underlag inför en biopsitagning gjord med TRUS där MR-kameran används för att lokalisera misstänkt patologiska områden i prostatan och på så sätt bestäms ett lämpligt insticksställe för biopsin. Syfte: Att undersöka MR-kamerans sensitivitet vid prostatacancer, både vid enbart bildtagning och vid MR-ledd biopsi. Metod: En systematisk litteraturstudie genomfördes där 12 artiklar granskades och sammanställdes till ett resultat i form av tabell. Resultat: Studierna visar en hög sensitivitet hos MR för att upptäcka både allmän och signifikant prostatacancer.   Slutsats: Resultatet från detta arbete visar att MR har en hög sensitivitet för prostatacancer och kan därför med stor säkerhet upptäcka patologiska områden inom prostatan. MR-bilderna kan även med fördel användas som ett effektivt diagnostiseringsverktyg av allmän och signifikant prostatacancer, särskilt i samband med transrektalt ultraljud. / Abstract: Prostate cancer is most often diagnosed by a prostate biopsy led by a transrectal ultrasound. Magnetic resonance tomography can also be used to find prostate cancer, and a diagnosis can then be made from the images. More commonly MRI is used as a basis for a biopsy done with TRUS where the MRI is used to localise suspected pathological areas in the prostate and in this way a suitable biopsy spot is chosen. Purpose: To examine the sensitivity of the MRI-camera for prostate cancer, both for imaging alone and for MRI-led biopsy. Method: A systematic literature review was performed where 12 articles were examined and compiled into a result presented as a chart.   Result: Shows a high sensitivity with MRI for finding both unsignificant and significant prostate cancer.   Conclusion: The results from this study shows that MRI has a high sensitivity for prostate cancer and can with great accuracy discover pathological areas in the prostate. The MRI images can advantageously be used as an effective diagnosing tool for general and significant prostate cancer, a specially combined with transrectal ultrasound.

abstract: Magnetic Resonance Imaging (MRI) is limited in speed and resolution by the inherently low Signal to Noise Ratio (SNR) of the underlying signal. Advances in sampling efficiency are required to support future improvements in scan time and resolution. SNR efficiency is improved by sampling data for a larger proportion of total imaging time. This is challenging as these acquisitions are typically subject to artifacts such as blurring and distortions. The current work proposes a set of tools to help with the creation of different types of SNR efficient scans. An SNR efficient pulse sequence providing diffusion imaging data with full brain coverage and minimal distortion is first introduced. The proposed method acquires single-shot, low resolution image slabs which are then combined to reconstruct the full volume. An iterative deblurring algorithm allowing the lengthening of spiral SPoiled GRadient echo (SPGR) acquisition windows in the presence of rapidly varying off-resonance fields is then presented. Finally, an efficient and practical way of collecting 3D reformatted data is proposed. This method constitutes a good tradeoff between 2D and 3D neuroimaging in terms of scan time and data presentation. These schemes increased the SNR efficiency of currently existing methods and constitute key enablers for the development of SNR efficient MRI. / Dissertation/Thesis / Ph.D. Electrical Engineering 2011

During image guided interventional radiology (IR) procedures, acute X-ray induced skin injuries may occur due to high absorbed patient skin dose. These procedures are highly dependent on X-ray imaging both for guiding fluoroscopy and high quality diagnostic image acquisitions. A dose metric that quantifies the peak absorbed skin dose (PSD) is therefore of great importance, both in terms of patient specific follow-up and for imaging protocol optimization. Presently, the cumulative interventional reference point (IRP) air Kerma is the most common skin dose estimation metric in use. This metric lacks several important dose contributions, such as pre-patient attenuation, air-to-skin medium correction, scattering from the patient and the support table, and fluence correction for actual source-to-skin distance. In this manuscript, we present a novel methodology for estimating the maximum absorbed skin dose by using dose related X-ray equipment parameters, such as peak tube voltage, support table position and IRP air Kerma obtained from radiation dose structured reports (RDSR) generated by modern IR equipment. In particular, Siemens Artis Zee (Siemens Healthineers, Erlangen, Germany) and Philips Allura Clarity (Philips, Amsterdam, Netherlands). The calculation process was automated by the development of a series of programming scripts in the PythonTM programming language v3.6 (Python Software Foundation), together with a database storing correction factors and machine specific parameters such as half-value layer (HVL). The proposed calculation model enables the implementation of a dose metric which corresponds better to absorbed skin dose than IRP air Kerma in clinical settings. However, extensive future work is required for a complete PSD implementation, in particular, the development of a skin dose map in which the spatial location of each irradiation event is tracked.

BACKGROUND: Although the Image Quality (IQ) indices calculated by objective Model observers contains more favourable characteristics compared to Figure Of Merits (FOM) derived from the more common subjective evaluations of modern digital diagnostic fluoroscopy units, like CDRAD or the Leeds test-objects, practical issues in form of limited access to unprocessed raw data and intricate laboratory measurements have made the conventional computational methods too inefficient and laborious. One approach of the Statistical Decision Variables (CDV) analysis, made available in the FluoroQuality software, overcome these limitations by calculating the SNR2rate from information entirely based on image frames directly obtained from the imaging system, operating in its usual clinical mode.      AIM: The overall aim of the project has been to make the proposed Model observer methodology readily available and verified for use in common IQ tests that takes place in a hospital based on simple measuring procedures with the default image enhancement techniques turned on. This includes conversion of FluoroQuality to MATLAB, assessment of its applicability on a modern digital unit by means of comparisons of measured SNR2rate with the expected linear response predicted by the classical Rose model, assessment of the methods limiting and optimized imaging conditions (with regard to both equipment and software parameters) and dose-efficiency measurements of the SNR2rate/Doserate Dose-to-information (DI) index including both routine quality control of the detector and equipment parameter analyses.      MATERIALS AND METHODS: A Siemens Axiom Artis Zee MP diagnostic fluoroscopy unit, a Diamentor transmission ionisation chamber and a small T20 solid state detector have been used for acquisition of image data and measurements of Air Kerma-area product rate (KAP-rate) and Entrance Surface Air Kerma rate (ESAK-rate without backscatter). Two sets of separate non-attached test-details, of aluminium and tissue equivalent materials respectively, and a Leeds test object were used as contrasting signals. Dose-efficiency measurements consisted of variation of 4 different parameters: Source-Object-Distance, Phantom PMMA thickness, Field size and Dose rate setting. In addition to these, dimensions of the test details as well as computational parameters of the software, like ROI size and number of frames, were included in the theoretical analyses.      RESULTS: FluoroQuality has successfully been converted to MATLAB and the method has been verified with SNR2rate in accordance with the Rose model with only small deviations observed in contrast analyses, most likely reflecting the methods sensitivity in observing non-linear effects. Useful guidelines for measurement procedures with regard to accuracy and precision have been derived from the studies. Results from measurements of the (squared) DI-indices indicates comparable precision (≤ 8%) with the highest performing visual evaluations but with higher accuracy and reproducibility. What still remains for the method to compete with subjective routine QC tests is to integrate the SNR2rate measurements in an efficient enough QA program.

p. 1-303 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-05-02T18:52:24Z No. of bitstreams: 1 5555555555555.pdf: 3446532 bytes, checksum: b8150cffebdae300ee77cdd045b05d64 (MD5) / Approved for entry into archive by Maria Creuza Silva(mariakreuza@yahoo.com.br) on 2013-05-04T17:39:48Z (GMT) No. of bitstreams: 1 5555555555555.pdf: 3446532 bytes, checksum: b8150cffebdae300ee77cdd045b05d64 (MD5) / Made available in DSpace on 2013-05-04T17:39:48Z (GMT). No. of bitstreams: 1 5555555555555.pdf: 3446532 bytes, checksum: b8150cffebdae300ee77cdd045b05d64 (MD5) Previous issue date: 2007 / Este estudo analisa o controle de riscos em radiodiagnóstico e seus condicionantes, considerando o marco regulatório vigente e identificando os diversos atores implicados nesta prática. O radiodiagnóstico é uma das principais ferramentas de diagnose da medicina moderna, sendo de fundamental importância para a detecção e acompanhamento de diversos agravos à saúde. Seu papel na saúde pública dependerá do controle e da qualidade dos exames e processos envolvidos, podendo representar um indispensável apoio diagnóstico ou um grave problema devido a informações diagnósticas incorretas ou incompletas, as exposições de pacientes, de trabalhadores e de indivíduos do público. Considerando que a vigilância sanitária, entendida como um campo de conhecimento científico e de práticas organizadas, visando à proteção da saúde, ainda está em processo de consolidação, além da descrição situacional, foram realizadas contribuições teóricas e metodológicas relacionadas ao conceito, controle e operacionalização da avaliação de riscos sanitários. Neste sentido, este trabalho propõe a utilização do conceito de risco potencial, com base no qual foi desenvolvido um modelo matemático para avaliação de risco potencial, utilizando os indicadores de controle de riscos estabelecidos no marco regulatório do radiodiagnóstico. Foram avaliados 94 procedimentos (7 de fluoroscopia, 14 de mamografia, 60 de radiografia convencional e 13 de tomografia) de 38 serviços de radiodiagnóstico no Estado da Bahia, analisando-se os condicionantes da situação encontrada. O estudo mostrou que dos 94 procedimentos avaliados, 30 (32%) (12 de radiografia, 4 de fluoroscopia, 6 de mamografia e 8 de tomografia) tinham nível de risco potencial aceitável; 18 (19%) (11 de radiografia, 1 de fluoroscopia, 3 de mamografia e 3 de tomografia) tinham nível de risco potencial tolerável e 46 (49%) (37 de radiografia, 2 de fluoroscopia, 5 de mamografia e 2 de tomografia) tinham nível de risco potencial inaceitável. Com relação aos serviços, apenas 2 unidades (5,3%) (uma pública e uma privada) estavam com todos os procedimentos em nível de risco potencial aceitável. 9 (23,7%) serviços (5 público e 1 privado) estavam com, pelo menos, um procedimento com nível de risco potencial tolerável e 27 (71%) serviços (7 público e 20 privado) possuíam, pelo menos, um procedimento com nível de risco potencial inaceitável. As análises dos indicadores de controle de riscos mostraram que os principais condicionantes da situação encontrada dizem respeito à ausência dos fundamentos de proteção radiológica e qualidade da imagem nas diretrizes curriculares da formação dos médicos e médicos especialistas; produção e comercialização de equipamentos e produtos para radiodiagnóstico sem registro na ANVISA; incapacidade da vigilância sanitária fiscalizar, anualmente, todos os serviços e ausência completa da atuação dos conselhos profissionais no acompanhamento e controle das práticas de seus profissionais. Assim, a utilização do conceito de risco potencial e de um modelo para sua operacionalização possibilitou avançar no sentido de melhor entender as especificidades e as possibilidades de ação do Sistema Nacional de Vigilância Sanitária, como autoridade reguladora no controle de riscos em radiodiagnóstico, bem como dos diversos atores que atuam nesta área. / Salvador

Inledning: Miktionsuretrocystografi (MUCG) är en röntgenundersökning som används vid diagnostisering av vesikoureteral reflux på barn. Undersökningen är både fysiskt och psykiskt påfrestande och för barn kan det upplevas som en ångestfylld undersökning. Föräldrarna har en viktig roll vid undersökningen och röntgensjuksköterskan behöver ha kunskap om hur barnens ångest kan lindras för att kunna hjälpa föräldrar att stötta sina barn. Syfte: Syftet med denna litteraturöversikt var att belysa faktorer som kan minska ångest hos barn inför och under en MUCG-undersökning. Metod: Studien genomfördes som en allmän litteraturöversikt. En systematisk litteratursökning i databaserna PubMed och CINAHL utfördes. Tolv vetenskapliga artiklar vilka svarade på syftet valdes ut till kvalitetsgranskning, analyserades därefter och resultatet av detta identifierades i kategorier. Resultat: Ur dataanalysen identifierades tre kategorier som beskriver faktorer som kan minska barns ångest; information och förberedelser, vuxnas påverkan på barnet och alternativa metoder. Konklusion: Information och förberedelser samt påverkan från föräldrarna har en stor betydelse för barns ångest. Genom ökad förståelse för dessa faktorer kan röntgensjuksköterskan stötta både barnen och föräldrarna under undersökningen samt medverka till utformning av nya rutiner. / Introduction: Voiding cystourethrogram (VCUG) is an x-ray examination that is used to diagnose vesicoureteral reflux in children. The examination is both physically and mentally stressful and for children it can be experienced as an anguished examination. Parents have an important role in the examination and the radiographer needs to know how children's anxiety can be eased in order to help parents support their children. Children’s anxiety can be demonstrated in several ways during the examination, which may complicate the diagnosis. Purpose: The aim of this literature review was to highlight factors that may reduce anxiety in children before and during a VCUG examination. Method: The study was performed as a literature review. A systematic literature search in the databases PubMed and CINAHL was performed. Twelve scientific articles which replied to the aim of this study were collected for quality review, then those articles were analyzed and the result were divided into categories. Results: From the data analysis three categories were identified to describe factors that can reduce children’s anxiety; information and preparation, adult influence on the child and alternative methods. Conclusion: Information and preparation as well as the influence of parents have great importance to children’s anxiety. Through increased understanding, the radiographer can support both the children and parents during the examination and also contribute to the design of new routines.

Esta dissertação apresenta o uso de técnicas para o estudo de layout e avaliação de desempenho do setor de radiologia de um hospital universitário. A dissertação foi elaborada em formato de três artigos científicos, cujos temas e objetivos são: (i) aplicar a análise de conglomerados como etapa preliminar do planejamento sistemático de layout (Systematic Layout Planning – SLP) para planejar o layout do setor de radiologia de um hospital universitário; (ii) realizar uma revisão sistemática das técnicas e conceitos adotados para planejar layouts em ambientes hospitalares; e (iii) usar cartas de controle para avaliar o desempenho dos médicos do setor de radiologia de um hospital universitário. Os métodos desenvolvidos para os itens (i) e (iii) foram avaliados através da aplicação de estudos de caso, em exemplos com dados reais. Os métodos propostos para o item (i) foram adaptados especificamente para este caso. Para o item (ii) a metodologia proposta foi de pesquisa exploratória e descritiva, buscando referências na literatura para estudar e discorrer acerca do tema. Para o item (iii), o método foi implementado na prática em um ambiente onde existem apenas estudos de caráter conceitual. Os métodos apresentaram resultados satisfatórios em todos os casos. No primeiro artigo, chegou-se a um layout considerado ideal, separando zonas de ruído e de silêncio, e potencialmente melhorando a produtividade do setor de radiologia. Já no segundo artigo, conceitos, premissas e técnicas sobre o planejamento de layout em hospitais foram apresentados e difundidos, e lacunas e direcionamentos da pesquisa foram apontados. No terceiro artigo, foi possível avaliar o desempenho dos radiologistas através das cartas de controle e calcular a capacidade do processo usando os índices Cp e Cpk. / This study presents the use of techniques for the layout study and performance evaluation in a radiology sector of an university hospital. The study was performed in the form of three scientific articles, whose themes and objectives are: (i) to apply clustering analisys as the preliminary step of Systematic Layout Planning (SLP) to plan the layout of the radiology sector of a universitary hospital; (ii) to carry out a systematic review of the techniques and concepts adopted to plan layouts in hospital settings; and (iii) to use control charts to evaluate the performance of radiologists in a university hospital. The methods developed for items (i) and (iii) were evaluated through the application of case studies in examples with real data. The proposed methods for item (i) were adapted specifically for this case. For item (ii), the methodology proposed was exploratory and descriptive, seeking references in the literature to study and discuss the subject. For item (iii), the method was performed in a case study in an environment where there are only conceptual studies. The methods presented satisfactory results in all cases. In the first article, we reached an ideal layout, separating zones by noise and silence, and potentially improving the productivity of the radiology sector. In the second article, concepts, premises and techniques about layout planning in healthcare were presented and disseminated, gaps and directions of the research were pointed out. In the third article, it was possible to evaluate the performance of the radiologists through the control charts and to calculate the capacity of the process using the indexes Cp and Cpk.