The Miniature Robotic Needling Device in Brachytherapy: Design and Modeling - An Approach Towards Smart Needle System

A novel miniature robotic needling device was developed to assist clinicians to improve the flexibility of needle insertion and accuracy of seed deposition in brachytherapy. The mechanical modeling of needle behavior that can estimate the trajectory of the needle tip during needle insertion was investigated, by incorporating the force and torque feedback from the needle. Based on the beveled-tip and rigid-beam model of the individual needle, the predictive control was applied to compensate on the lateral components of the generalized interactive force change, which is responsible for the disturbance of the surrounding tissue displacement and deformation. Thus, the needle deflection can be minimized during the insertion procedure. Experiments were performed and the results were evaluated with the clinical justification of tumor target coverage and organ at risk. The device model and control strategy were validated in the capability of the minimal needle deflection and the accurate needle tip displacement. This study has the clinical significance and provides a new approach towards smart needle system with broader applications in various clinical settings.