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Title: Robotic assistant for MRI-guided ablation of the liver
Author: Franco, Enrico
ISNI:       0000 0004 6495 5148
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2015
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Robotic devices represent a promising solution to the space limitations of cylindrical MRI scanners, potentially allowing more accurate and faster intervention for the benefit of patients and clinicians. This thesis presents the design, control, and experimental evaluation of a robotic assistant for MRI-guided percutaneous intervention of the liver. The robot provides remotely controlled alignment of a needle guide inside the MRI scanner bore and employs manual needle insertion outside the bore. A graphical user interface allows planning the procedure based on the MR images. A systems engineering process for requirements analysis and concept generation for medical devices is employed in order to provide a solid basis for the design. This approach involves multiple methods and defines a specific workflow with the aim of generating a comprehensive set of requirements and corresponding solutions in order to address the clinical needs. The main features and functionalities of the robot are analysed and verified with a first prototype. Particular attention is paid to the design of a suitable pneumatic actuation and to the position control of the robot. In this respect, different control algorithms are designed and compared with simulations and experiments, achieving a higher positioning accuracy than previously reported for similar systems. A fully functional prototype is then presented and evaluated with extensive experiments. The effects of the system on the quality of the MR images and the robot targeting accuracy are assessed in high-field closed-bore MRI scanners. The advantages of robot-assisted needle insertion over the conventional manual procedure in terms of accuracy and time saving are highlighted with a comparative phantom study. The functionality of the system is verified with an exploratory clinical trial on one patient. Finally, the use of pneumatic actuation for teleoperated needle insertion is investigated and suitable control strategies are presented, in view of a further enhancement of the robot functionalities in following design iterations.
Supervisor: Ristic, Mihailo ; Rodriguez y Baena, Ferdinando Sponsor: National Institute for Health Research
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral