title: A novel end-effector design for robotics in image-guided needle procedures.
abstract: BACKGROUND
  Robotic end-effectors are being developed to facilitate image-guided minimally invasive needle-based procedures, such as tumour ablation, biopsy, thoracentesis and blood sampling.
  
  
  METHODS
  A novel mechanical end-effector was designed to address the challenges associated with any major needle-based procedure, focusing on liver biopsy and ablation. In this end-effector embodiment, the distal end of a single articulating arm can grip needles and instruments and allows a fairly high number of degrees of freedom of movement during the complex motions associated with positioning and driving needles, as well as the periodic motions associated with breathing patterns. Tightening a cable that runs through the articulations fixes the arm in a rigid state, allowing insertion of the gripped needle.
  
  
  RESULTS
  A design is presented that will require electro-mechanical stimulation and remote joystick control. The associated forces of cranial-caudal motion of soft tissue organs affects design constraints. A simulation study defined the process with tissue phantoms with mechanical properties in the range of hepatic tissue and the overlying abdominal wall. The robotic arm coupled with our end-effector could be deployed in an image-guided interventional suite.
  
  
  CONCLUSIONS
  Such a switch-able and flexible mode for a robotic arm could overcome much of the current limitations for automated needle placements for mobile targets, and could mitigate risks from breathing or patient motion with a rigid needle gripper in place.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
authors.forename: D
authors.initials: D
authors.lastname: Sun
authors.forename: C
authors.initials: C
authors.lastname: Willingham
authors.forename: A
authors.initials: A
authors.lastname: Durrani
authors.forename: P
authors.initials: P
authors.lastname: King
authors.forename: K
authors.initials: K
authors.lastname: Cleary
authors.forename: B
authors.initials: B
authors.lastname: Wood
mesh_terms: D000818:Animals; D001707:Biopsy, Needle / Q000295:instrumentation*; D002417:Cattle; D004867:Equipment Design; D012371:Robotics / Q000295:instrumentation*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*