1,720,995 research outputs found

    Consolidation radiotherapy to bulky or semibulky lesions in the management of stage III-IV diffuse large B cell lymphomas

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    Background: To assess the impact on survival of consolidation radiotherapy to bulky or semibulky lesions in patients with advanced diffuse large B cell lymphoma (DLCL) in complete remission after primary chemotherapy. Patients and Methods: Ninety-four patients with stage III-IV DLCL and bulky (greater than or equal to 10 cm) or semibulky lesions (6-9 cm) in complete remission after primary chemotherapy were reviewed. Forty patients received consolidation radiotherapy to bulky (n = 20) or semibulky lesions (n = 20), while 54 (18 with bulky disease) did not. Twenty-eight patients were irradiated to the involved field and 12 to the extended field with a dose of 30-46 Gy. Results In patients with bulky disease, consolidation radiotherapy prevented relapses involving exclusively the bulky area, prolonged time to relapse (TTR) (median 41+ vs. 18 months; p = 0.05) and improved 5-year overall survival (OS) (73 vs. 57%; p = 0.05). Consolidation radiotherapy reduced relapses with in the semibulky area, prolonged TTR (median 26+ vs. 20 months; p = 0.01) and improved 5-year OS (59 vs. 41%; p = 0.09) also in patients with semibulky lesions. Multivariate analyses confirmed the independent association between consolidation radiotherapy and survival, and showed that a dose greater than or equal to 36 Gy was related to a longer OS, while the extension of the radiotherapy field did not modify outcome. No treatment-related deaths were observed. Four patients developed a second malignancy, none of whom had undergone consolidation radiotherapy. Conclusions: Consolidation radiotherapy to bulky or semibulky lesions significantly improved the outcome in patients with advanced DLCL in complete remission after primary chemotherapy. Involved-field irradiation with 36-45 Gy made a prolonged disease control possible without either lethal toxicity or a higher incidence of second malignancies. Copyright (C) 2000 S. Karger AG, Basel

    Feasibility of [F-18]FDG-PET and coregistered CT on clinical target volume definition of advanced non-small cell lung cancer

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    Aim. To prospectively evaluate the impact of coregistered positron emission tomography (PET) and computed tomography (CT) in 3D conformal radiotherapy (3D-CRT) planning in patients with non-small lung cancer (NSCLC). Methods. Twenty-one patients (median age: 57 years; range: 42-80 years) referred to 3D-CRT for NSCLC were recruited. Positron emission tomography with F-18-fluorodeoxyglucose ([F-18]FDG-PET) and conventional CT images were coregistered (PET/CT images) using a commercial software package based on surface matching technique. Neoplastic areas were contoured on [F-18]FDG-PET images with the aid of the correspondent CT image by a nuclear medicine physician. CT images and their relative PET contours were then transferred to treatment planning system. A radiation oncologist firstly contoured clinical target volumes (CTV) on CT scan alone (CTV-CT), and then on coregistered PET/CT images (CTV-PET/CT). CTV-CT and CTV-PET/CT were compared for each patient; a difference higher than 25% was considered of clinical relevance. Results. Three patients were shifted to pallative radiotherapy for metastatic disease or very large tumor size, showed by [F-18]FDG-PET. Of the remaining 18 patients a CTV change, after inclusion of PET/CT data, was observed in 10/18 cases (55%): larger in 7/18 (range 33279%) and smaller in 3/18 patients (range 26-34%), mainly due to inclusion or exclusion of lymph-nodal disease and to better definition of tumor extent. CTV changes smaller than 25% occurred in the remaining 8/18 patients. Conclusion. [F-18]FDG-PET and CT images co-registration in radiotherapy treatment planning led to a change in CTV definition in the majority of our patients, which may significantly modify management and radiation treatment modality in these patients

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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
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