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Utvärdering av patientcentrerings metoder inom Datortomografi: en fantomstudie som jämför automatisk 3D-kamera baserad och manuell centrering för brus och dosoptimering
No full textBackground: The increasing use of computed tomography (CT) raises concerns about radiation-induced cancer. Simultaneously, advancements such as automatic exposure control (AEC), tube current modulation (TCM) and bowtie filter aim to reduce radiation dose without compromising image quality. Recently, 3D camera-based systems have been introduced to improved patient centering and support dose optimization. Aim: The aim of this study was to compare the effectiveness of 3D camera-based and manual centering by radiographers, of phantoms, to evaluate mis-centering errors in CT-imaging. Method: Two thoracic phantoms were scanned on two Siemens CT systems: Somatom Drive and Naeotom Alpha, at different vertical table positions from isocenter. One phantom was also scanned using both manual and 3D camera-based centering. CTDIvol values were collected for radiation dose analysis, and image noise was assessed using region of interest (ROI) standard deviation. Scans were repeated to ensure consistency, and statistical analysis was performed using the Wilcoxon signed rank test. Results: Positioning below the patient isocenter increased radiation dose, while positioning above patient isocenter reduced dose by up to 32 %. Manual centering achieved minimal deviation from isocenter and maintained lower CTDIvol. In contrast, 3D camera-based centering consistently overestimated table height, resulting in significantly increased dose values across both scanners. Discussion: Vertical miscentering affected radiation dose more than image quality. Although 3D camera-based centering was more reproducible, it was less accurate than manual positioning. Conclusion: Manual centering achieved higher accuracy than 3D camera systems. Combining skilled radiographers with automated tools offers the best strategy to ensure optimal image quality, dose efficiency and patient safety in CT imagin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Utvärdering av patientcentrerings metoder inom Datortomografi: en fantomstudie som jämför automatisk 3D-kamera baserad och manuell centrering för brus och dosoptimering
No full textBackground: The increasing use of computed tomography (CT) raises concerns about radiation-induced cancer. Simultaneously, advancements such as automatic exposure control (AEC), tube current modulation (TCM) and bowtie filter aim to reduce radiation dose without compromising image quality. Recently, 3D camera-based systems have been introduced to improved patient centering and support dose optimization. Aim: The aim of this study was to compare the effectiveness of 3D camera-based and manual centering by radiographers, of phantoms, to evaluate mis-centering errors in CT-imaging. Method: Two thoracic phantoms were scanned on two Siemens CT systems: Somatom Drive and Naeotom Alpha, at different vertical table positions from isocenter. One phantom was also scanned using both manual and 3D camera-based centering. CTDIvol values were collected for radiation dose analysis, and image noise was assessed using region of interest (ROI) standard deviation. Scans were repeated to ensure consistency, and statistical analysis was performed using the Wilcoxon signed rank test. Results: Positioning below the patient isocenter increased radiation dose, while positioning above patient isocenter reduced dose by up to 32 %. Manual centering achieved minimal deviation from isocenter and maintained lower CTDIvol. In contrast, 3D camera-based centering consistently overestimated table height, resulting in significantly increased dose values across both scanners. Discussion: Vertical miscentering affected radiation dose more than image quality. Although 3D camera-based centering was more reproducible, it was less accurate than manual positioning. Conclusion: Manual centering achieved higher accuracy than 3D camera systems. Combining skilled radiographers with automated tools offers the best strategy to ensure optimal image quality, dose efficiency and patient safety in CT imagin
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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