Simulation du Mouvement Pulmonaire pour un Traitement Oncologique - Application à la Radiothérapie et à l'Hadronthérapie

ISBN-13: 978-613-1-56604-2 ISBN-10:6131566046L'objectif de ces travaux est d'améliorer le traitement curatif du cancer du poumon par radiothérapie conformationnelle et hadronthérapie. Il s'agit de simuler, dans un cas concret, le mouvement et les déformations des poumons d'un patient. Grâce à plusieurs collaborations médicales, nous avons défini des conditions initiales et des conditions limites pour obtenir un modèle biomécanique suivant les lois de la mécanique des milieux continus et personnalisé à un patient. Le calcul mécanique est réalisé sur un poumon fixé au niveau du médiastin et soumis à une dépression homogène tout autour avec prise en compte des grandes déformations. Une contrainte supplémentaire de gestion du contact de la surface du poumon autorisant le glissement est ajoutée pour reproduire le comportement réel des organes et plus spécialement celui de l'enveloppe des poumons : la plèvre. Une étude a par ailleurs été menée sur la conversion des données prédites du modèle en scanner 4D afin de préparer la dosimétrie

Visualisation of Physical Lung Simulation: an Interactive Application to Assist Physicians

International audienceRadiation therapy of cancer necessitates accurate tumour targeting. Unfortunately, during the treatment the tumour and the related organs can undergo large displacement and deformation. Physicians need an estimation of these movements, for an adapted therapy. In this paper, we propose a methodology to provide physicians with reconstructed 4D (3D+time) CT scans, considered as essential data. Moreover we propose an interactive visualisation tool, permitting the exploration of reconstructed 4D CT scans as well as the generation of new CT scan sections in any direction of the 3D space

Virtual Reality Simulation of Liver Biopsy with a Respiratory Component

International audienceThe field of computer-based simulators has grown exponentially in the last few decades, especially in Medicine. Advantages of medical simulators include: (1) provision of a platform where trainees can practice procedures without risk of harm to patients; (2) anatomical fidelity; (3) the ability to train in an environment wherein physiological behaviour is observed, something that is not permitted where in-vitro phantoms are used; (4) flexibility regarding anatomical and pathological variation of test cases that is valuable in the acquisition of experience; (5) quantification of metrics relating to task performance that can be used to monitor trainee performance throughout the learning curve; and (6) cost effectiveness. In this chapter, we will focus on the current state of the art of medical simulators, the relevant parameters required to design a medical simulator, the basic framework of the simulator, methods to produce a computer-based model of patient respiration and finally a description of a simulator for ultrasound guided for liver biopsy. The model that is discussed presents a framework that accurately simulates respiratory motion, allowing for the fine tuning of relevant parameters in order to produce a patient-specific breathing pattern that can then be incorporated into a simulation with real-rime haptic interaction. Thus work was conducted as part CRaIVE collaboration [1], whose aim is to develop simulators specific to interventional radiology

Simulated Motion Artefact in Computed Tomography

International audienceWe propose a simulation framework to simulate the computed tomography acquisition process. It includes five components: anatomic data, respiration modelling, automatic parametrisation, X-ray simulation, and tomography reconstruction. It is used to generate motion artefacts in reconstructed CT volumes. Our framework can be used to evaluate CT reconstruction algorithm with motion artefact correction in a controlled environment

Resolution of Non-Linear Problems In Realistic-Lung-Inflating Simulation with Finite Element Method.

International audienceHadrontherapy treatment needs accurate tumour targeting, which is difficult for lung cancer due to breathing motions. We propose to quantify lung deformation and displacement by a simulation technique based on the geometrical and mechanical properties of organs. Thereby, we model lung behaviour by a 3D dynamic deformable model derived from continuous mechanics, computed with finite elements method (FEM)

CT Scan Merging to Enhance Navigation in Interventional Radiology Simulation

International audienceWe present a method to merge two distinct CT scans acquired from dif- ferent patients such that the second scan can supplement the first when it is missing necessary supporting anatomy. The aim is to provide vascular intervention simula- tions with full body anatomy. Often, patient CT scans are confined to a localised region so that the patient is not exposed to more radiation than necessary and to increase scanner throughput. Unfortunately, this localised scanning region may be limiting for some applications where surrounding anatomy may be required and where approximate supporting anatomy is acceptable. The resulting merged scan can enhance body navigation simulations with X-ray rendering by providing a com- plete anatomical reference which may be useful in training and rehearsal. An ex- ample of the use of our CT scan merging technique in the field of interventional radiology is described

Lung Mesh Generation to Simulate Breathing Motion with a Finite Element Method

International audienceNumerical modelling of lung behaviour during the respiration cycle is a difficult challenge due to its complex geometry and surrounding environment constraints. This paper presents an approach to simulate a patient's lung motion during inhaling and exhaling based on a continuous media mechanics model and solved with a finite element method. One of the key problems is an adequate lung mesh generation, which is specifically developed in this paper

Simulation of Lung Behaviour with Finite Elements : Influence of Bio-Mechanical Parameters

International audienceMotivated by medical needs, we propose to simulate lung deformation and motion during respiration to track tumours. This paper presents a model of lung behaviour based on a continuous media mechanics model and solved with a finite element method. The result is a simulation of a normal breathing, matching with patient customised data. Moreover, we carried out numerical experiments to evaluate our algorithms and to measure the influence and the relevance of mechanical parameters

Towards Accurate Tumour Tracking in Lungs

International audienceMotivated by radiotherapy and hadrontherapy improvement, we consider in a first step the potential of simple elastic mechanical modelling of the lung. We propose to simulate his deformation and motion during respiration towards tracking tumours. We present two approaches, based on finite-elements method and mass-spring system. For this, we suggest a personalised model based on the measurement of patient's physical and geometrical data

PoLAR: a Portable Library for Augmented Reality

International audienceWe present here a novel cross-platform library to facilitate research and development applications dealing with augmented reality (AR). Features include 2D and 3D objects visualization and interaction, camera flow and image manipulation, and soft-body deformation. Our aim is to provide computer vision specialists' with tools to facilitate AR application development by providing easy and state of the art access to GUI creation, visualization and hardware management. We demonstrate both the simplicity and the efficiency of coding AR applications through three detailed examples. PoLAR can be downloaded at http://polar.inria.fr and is distributed under the GPL licence