1. Declaration of Conflict of Interest or Relationship Speaker Name: Santhi Elayaperumal I have no conflicts of interest to disclose with regard to the subject matter of this presentation. 1

2. MRI-compatible Haptics: Strain sensing for real-time estimation of three dimensional needle deflection in MRI environments Y-L. Park 1, S. Elayaperumal 1, S.C. Ryu 1, B. Daniel 2, R. J. Black 3, B. Moslehi 3, and M.R. Cutkosky 1 1 Mechanical Engineering, Stanford University, Stanford, CA, United States 2 Radiology, Stanford University, Stanford, CA, United States 3 Intelligent Fiber Optic Systems Corporation, Santa Clara, CA, United States 2

3. Introduction  Challenges in the Manipulation of Tools in MRI-guided Interventions.  Lack of Sensing Capabilities & Tactile Cues in Medical Robotics.  MRI-Compatible Force & Deflection-Sensing Needle. Dan Stoianovici and PneuStep, JHU. 3 MRI of needle puncturing an abscess in the pelvis.

4. System Integration 4

5. 5 Fiber Bragg Grating (FBG) Technology InputTransmissionReflection FBG Optical Fiber Input Transmission Reflection 5 mm 5

6. Fiber Bragg Grating (FBG) Sensors  Wavelength Shifts Proportional to Strain.  Immune to Electromagnetic Interference.  Multiplexing/Demultiplexing Capabilities.  Small and Flexible.  High Resolution.  Temperature Sensitive. 6

7. Design & Fabrication 7

8. Beam Theory 8

9. Sensor Placement 9 Minimum Error Regions y 1 = 25 mm y 2 = 82 mm

10. Calibration 10

11. 11

12. Results & Animal Test Benchtop results show <0.1mm accuracy when calibrated for manufacturing tolerances. MRI of a mature male beagle’s prostate and needle prototype. Deflections of 2.0mm and 2.5mm along the x and z axes respectively (scale exaggerated to highlight flexing.) 12

13. Conclusions  FBG Sensors Successful in Estimating Tip Deflection and Profile in 3D.  No Image Artifact Resulted from Sensors.  Sensor Signal Was Not Affected by the Magnetic Field.  Possible Applications in:  Manual Needle Manipulation & Robotic Trajectory Planning (Position Sensing)  Tissue Deformation Validation Studies & Haptic Feedback (Force Sensing)  Cryosurgery & RF Ablation (Temperature Sensing)  etc. 13

14. 14 Future Work: Robotic Manipulator and Integrated System

15. Acknowledgements 15