Design and Validation of a CT- and MRI-Guided Robot for Percutaneous Needle Procedures

This paper describes the design and evaluation of the second generation of a robotic system called the light puncture robot for thoracic and abdominopelvic interventional radiology procedures under CT and MRI guidance. It is mounted on the patient's body and positions and inserts the needle according to the trajectory and target chosen by the radiologist in the image. The mechanical design is described in detail along with its forward and inverse kinematics. The robot can be segmented and registered fully automatically in both imaging modalities. Phantom experiments in the CT scanner and preliminary feasibility experiments in the MRI are described, showing a targeting accuracy of 3.3 +/- 1.7 mm in gelatin for depths ranging from 30 to 90 mmand needle orientations of -13 degrees to + 15 degrees about normal from the patient's skin. A detailed error analysis is discussed along with potential improvements in the system. The potential clinical advantages of the system include higher targeting accuracy for complex dual obliquity trajectories, the need for fewer images, and improved accessibility to MRI-guided interventions.