Reconnaissance de l'ecrit dynamique application à l'analyse de texte

Nous présentons dans cette publication un nouveau système dédié à la reconnaissance de l'écriture dynamique. Il apparaît comme une alternative entre les assistants personnels (Personal Digital Assistants) du commerce qui sont très contraignants pour l'utilisateur et les moteurs de reconnaissance automatique de l'écriture cursive développés en laboratoire. Ces derniers n'ont pas encore atteint un niveau de performances commercialisable. Le traitement complet, de l'acquisition à la lecture, est associé à une interface utilisateur. Les résultats obtenus sur une base de textes omni-scripteur sont très encourageants. Ils peuvent êtres améliorés par l'utilisation d'un nouvel expert lexical qui adapte la reconnaissance au scripteur

Electronic Letters on Computer Vision and Image Analysis 5(2):87-97, 2005 Self-supervised adaptation for on-line script text recognition

We have recently developed in our lab a text recognizer for on-line texts written on a touch-terminal. We present in this paper several strategies to adapt this recognizer in a self-supervised way to a given writer and compare them to the supervised adaptation scheme. The baseline system is based on the activationverification cognitive model. We have designed this recognizer to be writer-independent but it may be adapted to be writer-dependent in order to increase the recognition speed and rate. The classification expert can be iteratively modified in order to learn the particularities of a writer. The best self-supervised adaptation strategy is called prototype dynamic management and gets good results, close to those of the supervised methods. The combination of supervised and self-supervised strategies increases accuracy again. Results, presented on a large database of 90 texts (5,400 words) written by 38 different writers are very encouraging with an error rate lower than 10 %. Key Words: handwriting recognition, supervised adaptation, self-supervised adaptation, model-based classifier.

2 Hybrid generative/discriminative classifier for

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Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro-CT imaging

International audiencePurpose: Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)/CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al2O3:C crystals. Methods: CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB/c mice weighing 27.1 +/- 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated. Results: CTDI measurements were between 78.0 +/- 2.1 and 110.7 +/- 3.0 mGy for the rat-like phantom and between 169.3 +/- 4.6 and 203.6 +/- 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse-like phantom. OSLDs exhibited a reproducibility of 2.4% and good linearity was found between 60 and 450 mGy. The energy scaling factor was calculated to be between 1.80 +/- 0.16 and 1.86 +/- 0.16, depending on protocol used. In phantoms, mean doses to tissue over a whole-body CT examination were ranging from 186.4 +/- 7.6 to 234.9 +/- 7.1 mGy. In mice, mean doses to tissue in the mouse trunk (thorax, abdomen, pelvis, and flanks) were between 213.0 +/- 17.0 and 251.2 +/- 13.4 mGy. Skin doses (3 OSLDs) were much higher with average doses between 350.6 +/- 25.3 and 432.5 +/- 34.1 mGy. The dose delivered during a topogram was found to be below 10 mGy. Use of the multimouse bed of the system gave a significantly 20%-40% lower dose per animal (p < 0.05). Conclusions: Absorbed doses in micro-CT were found to be relatively high. In micro-SPECT/CT imaging, the micro-CT unit is mainly used to produce a localization frame. As a result, users should pay attention to adjustable CT parameters so as to minimize the radiation dose and avoid any adverse radiation effects which may interfere with biological parameters studied. (C) 2013 American Association of Physicists in Medicine

PEC-PRO: A new prognostic score from a series of 87 patients with localized perivascular epithelioid cell neoplasms (PEComas) treated with curative intent

International audienceBackground: Perivascular epithelioid cell neoplasms (PEComas) encompass a heterogeneous family of mesenchymal tumors. Previously described clinicopathologic features aimed at distinguishing benign from malignant variants but lacked prognostic value.Methods: This retrospective analysis examined clinicopathologic data from patients who had localized PEComa across French Sarcoma Network centers. The authors analyzed 12 clinicopathologic features in a Cox proportional hazard framework to derive a multivariate prognostic risk model for event-free survival (EFS). They built the PEComa prognostic score (PEC-PRO), in which scores ranged from 0 to 5, based on the coefficients of the multivariate model. Three groups were identified: low risk (score = 0), intermediate risk (score = 1), and high risk (score ≥ 2).Results: Analyzing 87 patients who had a median 46-month follow-up (interquartile range, 20-74 months), the median EFS was 96.5 months (95% confidence interval [CI], 47.1 months to not applicable), with 2-year and 5-year EFS rates of 64.7% and 58%, respectively. The median overall survival was unreached, with 2-year and 5-year overall survival rates of 82.3% and 69.3%, respectively. The simplified Folpe classification did not correlate with EFS. Multivariate analysis identified three factors affecting EFS: positive surgical margins (hazard ratio [HR], 5.17; 95% CI, 1.65-16.24; p = .008), necrosis (HR, 3.94; 95% CI, 1.16-13.43; p = .030), and male sex (HR, 3.13; 95% CI, 1.19-8.27; p = 0.023). Four variables were retained in the prognostic model. Patients with low-risk PEC-PRO scores had a 2-year EFS rate of 93.7% (95% CI, 83.8%-100.0%), those with intermediate-risk PEC-PRO scores had a 2-year EFS rate of 67.4% (95% CI, 53.9%-80.9%), and those with high-risk PEC-PRO scores had a 2-year EFS rate of 2.3% (95% CI, 0.0%-18.3%).Conclusions: The PEC-PRO score reliably predicts the risk of postoperative recurrence in patients with localized PEComa. It has the potential to improve follow-up strategies but requires validation in a prospective trial

No Geographical Inequalities in Survival for Sarcoma Patients in France: A Reference Networks' Outcome?

International audienceSimple Summary As patients with rare cancers face specific problems, reference networks have been developed in several European countries and then at the European level to improve their management. In some cases, the specialized centers belonging to reference networks provide remote services (specialized diagnosis review, discussion in the Multidisciplinary Tumour Board, etc.) to increase access to these services. Using data from the national sarcoma reference network implemented in France (NETSARC+), the IGeAS research program assesses the potential of its organization to address the geographical inequalities in cancer management. We analyze the individual, clinical, and geographical determinants of the overall survival of sarcoma patients in France. We found no association between the overall survival of sarcoma patients and variables measuring their social deprivation, remoteness from reference centers, and geographical context. Following previous results from the research program, this study suggests that reference network organization should be considered to reduce cancer inequalities. The national reference network NETSARC+ provides remote access to specialized diagnosis and the Multidisciplinary Tumour Board (MTB) to improve the management and survival of sarcoma patients in France. The IGeAS research program aims to assess the potential of this innovative organization to address geographical inequalities in cancer management. Using the IGeAS cohort built from the nationwide NETSARC+ database, the individual, clinical, and geographical determinants of the 3-year overall survival of sarcoma patients in France were analyzed. The survival analysis was focused on patients diagnosed in 2013 (n = 2281) to ensure sufficient hindsight to collect patient follow-up. Our study included patients with bone (16.8%), soft-tissue (69%), and visceral (14.2%) sarcomas, with a median age of 61.8 years. The overall survival was not associated with geographical variables after adjustment for individual and clinical factors. The lower survival in precarious population districts [HR 1.23, 95% CI 1.02 to 1.48] in comparison to wealthy metropolitan areas (HR = 1) found in univariable analysis was due to the worst clinical presentation at diagnosis of patients. The place of residence had no impact on sarcoma patients' survival, in the context of the national organization driven by the reference network. Following previous findings, this suggests the ability of this organization to go through geographical barriers usually impeding the optimal management of cancer patients

Management and outcomes of adolescent and young adult sarcoma patients: results from the French nationwide database NETSARC

Abstract Background The initial management of patients with sarcoma is a critical issue. We used the nationwide French National Cancer Institute-funded prospective sarcoma database NETSARC to report the management and oncologic outcomes in adolescents and young adults (AYAs) patients with sarcoma at the national level. Patients and methods NETSARC database gathers regularly monitored and updated data from patients with sarcoma. NETSARC was queried for patients (15–30 years) with sarcoma diagnosed from 2010 to 2017 for whom tumor resection had been performed. We reported management, locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS) in AYA treated in French reference sarcoma centers (RSC) and outside RSC (non-RSC) and conducted multivariable survival analyses adjusted for classical prognostic factors. Results Among 3,227 patients aged 15–30 years with sarcoma diagnosed between 2010 and 2017, the study included 2,227 patients with surgery data available, among whom 1,290 AYAs had been operated in RSC, and 937 AYAs in non-RSC. Significant differences in compliance to guidelines were observed including pre-treatment biopsy (RSC: 85.9%; non-RSC 48.1%), pre-treatment imaging (RSC: 86.8%; non-RSC: 56.5%) and R0 margins (RSC 57.6%; non-RSC: 20.2%) (p < 0.001). 3y-OS rates were 81.1% (95%CI 78.3–83.6) in AYA in RSC and 82.7% (95%CI 79.4–85.5) in AYA in non-RSC, respectively. Whereas no significant differences in OS was observed in AYAs treated in RSC and in non-RSC, LRFS and PFS were improved in AYAs treated in RSC compared to AYAs treated in non-RSC (Hazard Ratios (HR): 0.58 and 0.83, respectively). Conclusions This study highlights the importance for AYA patients with sarcoma to be managed in national sarcoma reference centers involving multidisciplinary medical teams with paediatric and adult oncologists