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SU-F-J-204: Carbon Digitally Reconstructed Radiography (CDRR): A GPU Based Tool for Fast and Versatile Carbon imaging Simulation
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SU-E-J-83: Ion Imaging to Better Estimate In-Vivo Relative Stopping Powers Using X-Ray CT Prior-Knowledge Information
No full textScan path optimization with/without clustering for active beam delivery in charged particle therapy
No full textInvestigation of alternative imaging methods to improve accuracy in cancer therapy with carbon ions
Get PDFThe interest in carbon therapy for cancer treatment has been growing. However, in order to take full advantage of their depth-dose curve, precise knowledge of their range and patient interfaces is necessary. Range uncertainties in carbon therapy are significant due to the current method to determine the range, which uses X-ray CT and a calibration curve, and due to patient variations. The purpose of this dissertation was to find possible solutions to decrease range uncertainties.
The first method consisted in optimizing the elemental ionization values in the calculation of the relative stopping powers in order to obtain a better estimation of the calibration curve. The second method involved a phenomenological approach which predicted carbon paths trajectories
better than using straight path trajectories (root mean square error was reduced by 50 %). The third method, used multiple Bragg peak detection in order to obtain knowledge about the tumor edge position in a high
contrast medium. The method avoided irradiation of multiple angles/positions and provided 1mm accuracy in the determination of the tumor edge. Finally, the forth and last method proposed the use of charged particle (protons, carbons and heliums) radiography combined with X-ray
CT to obtain a patient-specific calibration curve to be used for carbon range calculations. The obtained results were extremely promising with maximum range errors of 1.5mm for helium radiography. These results suggest that helium radiography might be the method of choice for future carbon and proton treatment planning. The results derived in the
different chapters of this dissertation show that carbon therapy accuracy can be increased with respect to current clinical practice.The interest in carbon therapy for cancer treatment has been growing. However, in order to take full advantage of their depth-dose curve, precise knowledge of their range and patient interfaces is necessary. Range uncertainties in carbon therapy are significant due to the current method to determine the range, which uses X-ray CT and a calibration curve, and due to patient variations. The purpose of this dissertation was to find possible solutions to decrease range uncertainties.
The first method consisted in optimizing the elemental ionization values in the calculation of the relative stopping powers in order to obtain a better estimation of the calibration curve. The second method involved a phenomenological approach which predicted carbon paths trajectories
better than using straight path trajectories (root mean square error was reduced by 50 %). The third method, used multiple Bragg peak detection in order to obtain knowledge about the tumor edge position in a high
contrast medium. The method avoided irradiation of multiple angles/positions and provided 1mm accuracy in the determination of the tumor edge. Finally, the forth and last method proposed the use of charged particle (protons, carbons and heliums) radiography combined with X-ray
CT to obtain a patient-specific calibration curve to be used for carbon range calculations. The obtained results were extremely promising with maximum range errors of 1.5mm for helium radiography. These results suggest that helium radiography might be the method of choice for future carbon and proton treatment planning. The results derived in the
different chapters of this dissertation show that carbon therapy accuracy can be increased with respect to current clinical practice.DIPARTIMENTO DI ELETTRONICA, INFORMAZIONE E BIOINGEGNERIA28RAIMONDI, MANUELA TERESAALIVERTI, ANDRE
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
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
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