A MRI compatible concentric tube continuum robot with pneumatic actuation

Abstract

The aim of this study is to develop a magnetic resonance imaging (MRI) compatible robot to enable image guided interventions to enhance accuracy and reduce invasiveness. MRI provides exquisite soft tissue images, and fluid power is an enabler of its use in surgery. Its advantages are not completely explored yet because traditional electromagnetic actuators fail or cause artifacts in intense magnetic fields and the space inside the bore is limited. In order to overcome these constraints, we are designing and developing a compact and MRI-compatible system with an active cannula, operated by pneumatic actuation. The active cannula uses precurved concentric tubes, and the ensemble changes shape as tubes extend and spin axially. The robot employs MRI-compatible pneumatic cylinders with the goal of eliminating the artifacts that can be created by other actuation technologies. The robot is designed to perform a MRI-guided ablation of the hippocampus for patients with severe epilepsy using a proved MRI-compatible ablator. This thesis describes the development of the robot including design and workflow considerations, mechanical design, MRI-compatibility evaluation, control evaluation and both benchtop and in-scanner accuracy.