Oscar Acosta
University of Rennes
Internal medicineRadiologyUrologyMagnetic resonance imagingOncologyArtificial intelligencePattern recognitionProstateProstate cancerRectumPopulationToxicityNuclear medicineComputer visionMathematicsComputer scienceRadiation therapyVoxelMedicineSegmentationImage-guided radiation therapy
Publications 217
#1Martin A. Ebert (SCGH: Sir Charles Gairdner Hospital)H-Index: 26
#2Sarah L. Gulliford (UCLH: University College London Hospitals NHS Foundation Trust)H-Index: 23
Last. C. FiorinoH-Index: 7
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For decades, dose-volume information for segmented anatomy has provided the essential data for correlating radiotherapy dosimetry with treatment-induced complications. Dose-volume information has formed the basis for modelling those associations via normal tissue complication (NTCP) models and for driving treatment planning. Limitations to this approach have been identified. Many studies have emerged demonstrating that the incorporation of information describing the spatial nature of the dose di...
#1Jérémy BeaumontH-Index: 1
#2Oscar AcostaH-Index: 21
Last. Jurgen FrippH-Index: 2
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Brain morphometry performed with magnetic resonance (MR) imaging is affected by partial volume (PV) effects when single voxels contain the signal from two different tissues. This paper proposes a generalization of the MP2 RAGE sequence PV estimation model which accounts for transmitted magnetic field (B1^{+})inhomogeneities at 7T. Our simulation experiments demonstrated that the PV estimation error of the proposed model is significantly lower than the error obtained with the same model neglec...
#2Pierre FontaineH-Index: 3
Last. Oscar AcostaH-Index: 21
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In prostate cancer radiotherapy, biochemical recurrence has been traditionally predicted using radiomics approaches with however limited performance. The purpose of this work was to use a mechanistic in silico model of tumor growth and response to irradiation to obtain better predictions. A cohort of 76 patients with localized prostate adenocarcinoma having undergone external beam radiotherapy was used. Analogous digital tissues were built from pre-treatment MRI. The prescribed irradiation proto...
#2A. BarateauH-Index: 5
Last. Oscar AcostaH-Index: 21
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Several approaches have been proposed to generate pseudo computed tomography (pCT) from MR images for radiotherapy dose calculation. Quantification of errors in pCT has been reported using global scores disregarding spatial heterogeneity. The aim of this work was to propose a population voxel-based workflow allowing the local assessment of errors in the generation of pCTs from MRI. For the voxel-wise analysis to be anatomically meaningful, a robust customized inter-patient non-rigid registration...
#1Jérémy Beaumont (University of Rennes)H-Index: 1
#2Giulio Gambarota (French Institute of Health and Medical Research)H-Index: 7
Last. Jurgen Fripp (CSIRO: Commonwealth Scientific and Industrial Research Organisation)H-Index: 32
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PURPOSE To demonstrate that fluid and white matter suppression (FLAWS) imaging can be used for high-resolution T1 mapping with low transmitted bias field ( B1+ ) sensitivity at 7T. METHODS The FLAWS sequence was optimized for 0.8-mm isotropic resolution imaging. The theoretical accuracy and precision of the FLAWS T1 mapping was compared with the one of the magnetization-prepared two rapid gradient echoes (MP2RAGE) sequence optimized for low B1+ sensitivity. FLAWS images were acquired at 7T on si...
OBJECTIVE Purposes of this work were i) to develop an in silico model of tumor response to radiotherapy, ii) to perform an exhaustive sensitivity analysis in order to iii) propose a simplified version and iv) to predict biochemical recurrence with both the comprehensive and the reduced model. METHODS A multiscale computational model of tumor response to radiotherapy was developed. It integrated the following radiobiological mechanisms: oxygenation, including hypoxic death; division of tumor cell...
1 CitationsSource
#1Eugenia Mylona (French Institute of Health and Medical Research)H-Index: 4
#2Martin A. Ebert (UWA: University of Western Australia)H-Index: 26
Last. Renaud de Crevoisier (French Institute of Health and Medical Research)H-Index: 28
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Abstract Purpose /Objectives: Recent voxel-based studies have shown that the dose to specific rectal and urethro-vesical subregions is predictive of toxicities, following prostate cancer IMRT. The objective of this study was to validate the discriminatory power of these subregions with respect to the whole organs, in a large independent population. Material/Methods The validation cohort consisted of 450 patients, from the XXX(BLIND) trial, treated with 3D-CRT at 66-74 Gy. Previous voxel-based an...
4 CitationsSource
#1Pierre FontaineH-Index: 3
#2Oscar Acosta (French Institute of Health and Medical Research)H-Index: 21
Last. Adrien Depeursinge (University of Applied Sciences Western Switzerland)H-Index: 26
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In standard radiomics studies the features extracted from clinical images are mostly quantified with simple statistics such as the average or variance per Region of Interest (ROI). Such approaches may smooth out any intra-region heterogeneity and thus hide some tumor aggressiveness that may hamper predictions. In this paper we study the importance of feature aggregation within the standard radiomics workflow, which allows to take into account intra-region variations. Feature aggregation methods ...
1 CitationsSource
#2Joël CastelliH-Index: 17
Last. Mathieu HattH-Index: 39
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