Safety Consideration

1. Safety Consideration • Software limits on robot controller • Limit switches on the robot “wrist” to prevent excess rotations • Limit switches on the vertical travel • Contact detection on upper arm of robot • Enable button on hand pendant • E-Stop button on hand controller • Couch can lower for patient egress during power outage

2. Case Study 2 Automated Motion Correction – Tracking the Spine

3. Challenges of Spinal Treatments • The spine moves during treatment • Vertebrae can move independent of one another • Rigid transformation is not valid in most cases • Adjacent structures (spinal cord) necessitate high precision and accuracy

4. Traditional Radiation Therapy • Difficult to adequately immobilize the patient, internal structures, & the target • Image guidance (IGRT) confirms treatment setup but no compensation for target movement during the treatment • Implanted markers can increase accuracy but introduce additional challenges • Invasive • Delays time-to-treatment

5. Spine Tracking • Non-invasively registers non-rigid and bony anatomy landmarks • Internal markers or frames not required • Automatically tracks spine from DRR image pairs • Cervical, thoracic, lumbar and sacral • Sub-millimeter targeting accuracy, (0.52 +/- 0.22 mm)† ‡ † As measured in end-to-end testing. Reference: Muacevic, A., Staehler, M., Drexler, C., Wowra, B., Reiser, M. and Tonn, J. Technical description, phantom accuracy and clinical feasibility for fiducial-free frameless real-time image-guided spinal radiosurgery. J Neurosurgery Spine. ‡ Xsight accuracy specification of .95 mm.

6. How it Works… Step 3 Step 2 Step 1 • Hierarchical Mesh Tracking • Identifies unique bony structures • Enables registration of non-rigid skeletal anatomy • Estimates local displacements in bony features

7. How it Works… DRR (from CT) Live kV image Displacement Field Image A Image B

8. Spine Tracking Animation

9. Case Study 3 Automated Motion Compensation – Tracking Respriation

10. Respiratory Tracking • Challenges of respiratory motion • Respiratory-induced motion of tumors causes significant targeting uncertainty • Lung, liver, and pancreas • Traditional radiation therapy margins are not optimized for high-dose radiosurgery

11. Traditional Radiation Therapy • Solutions for compensating for motion plagued with repeatability and compliance issues • Healthy tissues is unnecessarily treated

12. Respiratory Tracking • Tightly contoured beams following tumor motion in real-time • Delivers throughout the respiratory cycle without gating or breath-holding • Instantly adapts to variations in breathing patterns • Proven accuracy • Systemic error of 0.70 +/- 0.33mm† ‡ † Reference: Dieterich S, Taylor D, Chuang C, Wong K, Tang J, Kilby W, Main W. The CyberKnife Synchrony Respiratory Tracking System: Evaluation of Systematic Targeting Uncertainty. ‡Synchrony clinical accuracy specification of 1.5 mm for moving targets.

13. How It Works… (1) • Two features to form the basis for accuracy LED markers on a special patient vest Gold markers, implanted prior to treatment

14. How It Works… (2) • Prior to treatment start: creation of dynamic correlation model LED’s are monitored in real time by a camera system Imaging system takes positions of markers at discrete points of time

15. How It Works… (2) • Prior to treatment start: creation of dynamic correlation model Imaging system takes positions of fiducials at discrete points of time Markers are monitored in real time by a camera system displacement displacement time time

16. How It Works… (3) • This process repeats throughout the treatment, updating and correcting beam delivery based upon the patient’s current breathing pattern displacement displacement time time

17. Synchrony Animation

18. Summary • There is a place for autonomous robotics in medicine • Special consideration must me taken to adapt to dynamic environment • Safety is most important requiring redundancy throughout • Greater demand for precision and accuracy will pave the way for future applications