This thesis presents the design, control and evaluation of an MR-Safe robotic system for transperineal prostate biopsy. The developed prototype combines a three-degree-of-freedom delta mechanism for translational positioning with a two-degree-of-freedom wrist mechanism for needle-guide orientation. The system is actuated using pneumatic stepper motors and non-metallic capstan transmissions, allowing the robot structure near the MRI scanner to be realised without conventional electromagnetic motors or metallic gear transmissions.
Analytical forward and inverse kinematics were implemented, including a corrected three-dimensional inverse-kinematic model for the delta stage. Position feedback was integrated using Ferris wheel sensors routed through Bowden tubes to electronics outside the MRI room. Experimental testing showed an average Euclidean positioning error of 2.59 mm after calibration. The prototype was tested inside a 1.5 T Siemens MRI scanner, where no visible robot-induced image artefacts or movement were observed in the tested configuration.
The work demonstrates the feasibility of a pneumatically actuated, capstan-driven MR-Safe robot for transperineal needle alignment and identifies key improvements for future MRI-guided phantom biopsy experiments.
