Numerous studies have demonstrated the efficacy of image-guided needle-based therapy, biopsy in the management of prostate cancer The accuracy of traditional prostate interventions performed using transrectal ultrasound (TRUS) is limited by image fidelity, needle template guides, needle deflection, tissue deformation Magnetic Resonance Imaging (MRI) is an ideal modality for guiding, monitoring such interventions due to its excellent visualization of the prostate, its sub-structure, surrounding tissues We have designed a comprehensive robotic assistant system that allows prostate biopsy, brachytherapy procedures to be performed entirely inside a 3T closed MRI scanner We present a detailed design of the robotic manipulator, an evaluation of its usability, MR compatibility