Kinematic and mechanical modelling of a novel 4-DOF robotic needle guide for MRI-guided prostate intervention

•MRI guided prostate biopsy can provide greater diagnosis of prostate cancer.•Physical needle placement guide is needed to maximize the benefits of MRI.•Confined workspace and limited access remain as a challenge for robotic guide systems.•A novel robotic mechanism has been designed to provide compact 4-DOF needle guide.•A proof-of-concept prototype has been fabricated and demonstrated the mechanism feasibility.