A Light-weight High-accuracy 4-DOF Robot for CT-image Guided Percutaneous Interventions

Percutaneous interventions, such as biopsy and brachytherapy, has been widely used in lung cancer diagnose and treatment, where CT image guided system is vital to provide the physicians with the position of the needle and target. However, robotic percutaneous interventions with CT image guidance can be challenging due to the narrow space of CT scanner and the image artifacts caused by metal components in the robot. The aim of this paper is to design a 4 degrees of freedom body-mounted robot to assist physicians with simplified surgical process and satisfactory targeting accuracy in the CT image guided lung percutaneous interventions. The proposed robot is designed to maintain compact size and light weight (less than 400 grams), making it possible to be mounted on the patient body to fully utilize the limited workspace of CT scanner and the non-metal materials were used in the robot to avoid image artifacts. Experiments were conducted to evaluate the CT compatibility and position accuracy of the robot. The CT image of the robot shows few image artifacts, proving the CT compatibility of the robot. The results show the average translational error of the prototype robot is 0.45mm and 0.58mm along X and Y axis, respectively, and the average of rotational error is 0.48 and 0.53 degrees around the X and Y axis, respectively.