1,721,030 research outputs found
Four-dimensional computed tomography in accelerated partial breast irradiation planning: single series from a phase III trial
No full textPurpose: The aim of our study was to evaluate the usefulness of the four-dimensional computed tomography (4DCT) in accelerated partial breast irradiation (aPBI) planning. Materials and methods: At our Institute, we have been treating the index quadrant with external intensity-modulated radiation therapy in a phase III trial. For this study, we selected a sample of 10 patients with right- or left-sided breast cancer and surgical clips at the excision site. Contouring of the target was performed both using three-dimensional computed tomography (3DCT) and 4DCT imaging. On both 3DCT and 4DCT, we recorded the clinical target volume (CTV) and the planning target volume (PTV) and the coordinates of the PTV centroid. We calculated the treatment plans, according to our protocol, using the contours drawn on the 3DCT and 4DCT and evaluated target coverage and sparing of organs at risk (OAR). Results: Median age of the patients was 63.5 years (range 52–75). The comparison between the 3DCT and 4DCT PTV volumes was not statistically significant (p = 0.79). Concerning centroid coordinates, the average absolute differences were 0.1 mm in the latero-lateral, 0.7 mm in the antero-posterior and 0.3 mm in the supero-inferior direction. No statistically significant differences were observed both in PTV coverage and OAR sparing; the 4D PTV contour is adequately covered when the plan based on the 3D contours is used. Target coverage was reduced on average by 1 % and no statistically significant difference was observed (p = 0.93). Conclusions: In our experience, no significant differences between PTV volumes, PTV coverage, OAR sparing and centroid position are evidenced when comparing 3DCT and 4DCT plans. Conventional 3DCT-based planning is adequate for aPBI
Primary lymphoma of bone: Outcome and role of surgery
No full textPurpose Primary bone lymphoma is a rare disease. Little is reported about surgical procedures in these patients. We evaluated a single-centre consecutive series of 21 patients for results, prognostic factors and surgical treatment.
Methods Patient ages ranged from 19 to 82 years. The most frequently affected site was the spine (six cases), followed by the ileum, femur and mandible (three cases each). Four patients were treated with chemotherapy and 17 with chemotherapy and radiation therapy. Six patients were affected by a pathological fracture. Surgery was performed in four patients (19 %), in two cases before chemotherapy, in one case during chemotherapy and in one case after chemotherapy and radiotherapy. Five patients died within the range of three to 36 months after diagnosis. Average follow-up of the remaining patients was 62.8 (19-145) months.
Results Overall survival was 74.2 % at five years. The only positive prognostic factor was complete remission after chemotherapy. A trend for better survival was present for International Prognostic Index (IPI) score (P = 0.051), under 40 years of age (P = 0.10) and abnormal lactate dehydrogenase (LDH) values (P = 0.10), but it did not reach statistical significance.
Conclusions Surgical treatment should be aimed at restoring function and eliminating pain while minimising delays in the chemotherapy schedule. When feasible, postponing surgery until after chemotherapy is advisable
Treatment of uterine sarcoma at the University of Florence from 1980-2001
No full textPURPOSE:
To correlate the treatment used in uterine sarcoma with outcome. The prognostic importance of pathology, clinical parameters and treatment are analyzed.
PATIENTS AND METHODS:
Forty patients (median age, 59 years; range, 37-85) with histologically verified uterine sarcoma were identified from a database compiled at the University of Florence from 1980 to 2001. Patients were followed for a median of 54 months (range, 3 months to 10 years). Twenty-four patients had leiomyosarcoma, 12 patients had mixed mullerian tumors, and 3 patients had endometrial stromal sarcoma. Stage I, II, III and IV tumors were identified in 22, 2, 9 and 7 patients, respectively. High, intermediate, low and unspecified grade sarcoma occurred in 9, 4, 5 and 22 patients, respectively.
RESULTS:
At the time of analysis, 58% of patients had died and 42% were alive, with a median survival of 2 years from the initial diagnosis. Cause-specific survival for the entire group was 81%, 41% and 25% at 1, 3 and 5 years, respectively. In our series, univariate analysis for cause-specific survival did not demonstrate statistical significance for histology, grade, stage or age. There appeared to be a significant impact for postoperative radiotherapy in reducing local recurrence with a total dose higher than 50 Gy.
CONCLUSIONS:
Our data favor treatment for uterine sarcoma with radical surgery plus irradiation, even in elderly patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Accuracy of a 3D laser/camera surface imaging system for setup verification of the pelvic and thoracic regions in radiotherapy treatments
No full textPurpose: The aim of this paper is to investigate the accuracy of a laser/camera surface imaging system (Sentinel) when used on patients treated in the thorax or pelvic regions and to evaluate system employment conditions and patient setup procedures that provide more accurate results. Methods: The system was tested on two groups of patients for whom different patient setup procedures and Sentinel employment conditions were considered. For the first group of 33 patients (FG) no changes to the usual setup procedures were made and a surface extension limited to the treated region was considered. For the second group of 14 patients (SG) the reproducibility of external body surfaces, including body parts not in close proximity to the treatment site, was optimized and a wider surface was captured. In all cases the system accuracy was evaluated comparing registration results from concurrent Sentinel and cone beam CT (CBCT) acquisitions for a total of 192 occasions. External body surfaces, extracted from planning CT studies, were used as reference in both cases, but for SG also surface data captured by Sentinel system at the first treatment were employed. Results: In the 90th percentile of the distributions reporting CBCT and Sentinel registration parameters, absolute differences for FG were less than 6.4 mm and 3.8°. Better performances were observed for SG (≤5.7 mm and 2°). Mean absolute differences between three translation and three rotation parameters of CBCT and Sentinel were: less than 3.5 mm and 2.1° and 3.7 mm and 1.3° in FG for thorax and pelvis, respectively, and less than 2.8 mm and 1° and 2.7 mm and 0.9° for pelvis and thorax, respectively, in SG. No advantage in considering surface data captured by Sentinel as a reference instead of the surface extracted from the planning CT was observed. Conclusions: The accuracy of Sentinel system in detecting errors is influenced by the extension and reliability of the surface used. When the reproducibility of external body surfaces was optimized differences between CBCT and Sentinel registration parameters resulted less than 5.7 mm and 2° in the 90% of the pelvis and thorax considered cases. No advantage in considering a Sentinel acquisition as reference was observed. © 2013 American Association of Physicists in Medicine
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
- …
