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Guidage robotisé d'une aiguille flexible sous échographie 3D pour la curiethérapie de la prostate

Abstract : In France, 25% to 30% of the 40,000 prostate cancer cases per year are treated with brachytherapy. During this procedure, about thirty needles are manually inserted into the prostate through the perineum using ultrasound images to locate the prostate and needles. Radioactive seeds are then inserted into the prostate specific pre-planned locations using needle cannula. The success of the operation is closely related to the distribution and homogeneity of the radioactive dose distribution in the prostate, therefore the precision with which the seeds are positioned. This accuracy is affected by many factors. Firstly, the prostate moves and deforms due to the insertion of the needles and to the movements of the ultrasonic probe. Secondly, the size of the prostate increases due to tissue inflammation and bleeding. Finally, the needles are very thin and could bend during insertion.The TIMC-IMAG laboratory (CAMI team) has developed a robotic system for transperineal needle insertion. This system is guided by 3D ultrasound to improve the precision, reliability and efficiency of the radioactive source positioning. These works showed a first proof of concept using a laboratory prototype. However the current approach can only partially correct prostate movements and deformations using 3D imaging methods. The correction does not take advantage of the rich information of this imaging modality: only the insertion depth is changed during the gesture. LIRMM (DEXTER team) recently developed an adaptive planning approach to guide a flexible needle during its insertion in percutaneous procedures. The proposed technique allows to update the path followed by the needle using online information from the visual feedback. This planning and control approach forms a closed-loop architecture and allows to compensate system disturbances (organ deformities, tissue inhomogeneity, etc.).The purpose of this thesis is to combine the expertise of the two laboratories to provide a flexible needle steering system for prostate brachytherapy purposes. This objective is achieved first by developing a needle tracking algorithm in 3D ultrasound. This algorithm deals with low visibility of the needles offered by this imaging modality, combined with various noises. These conditions complicate the detection of the needle. In order to improve the robustness of our algorithm, a search area is defined to detect the needle in the volume. This area is then determined by a predictive model, which is a first contribution of this manuscript. Control of the closed-loop planning needle is adapted to the specifications of the 3D ultrasound imaging system as well as those of the previously developed robot. This control is coupled to the needle visual feedback given by the detection algorithm. This device is tested on phantoms then on anatomical specimen to assess the viability and relevance of the proposed system.This work is therefore a first step towards a future clinical application of flexible needle steering. The entirely automatic insertion of flexible needle in clinic is a distant dream. However, the idea of an assistance system for needle insertion, where the clinician and the robot work together, is reachable from now.
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Submitted on : Thursday, January 25, 2018 - 10:05:08 AM
Last modification on : Sunday, October 25, 2020 - 7:06:42 AM
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  • HAL Id : tel-01692397, version 1


Paul Mignon. Guidage robotisé d'une aiguille flexible sous échographie 3D pour la curiethérapie de la prostate. Urologie et Néphrologie. Université Grenoble Alpes, 2016. Français. ⟨NNT : 2016GREAS019⟩. ⟨tel-01692397⟩



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