REGULAR CONTENT
Final ID
490
Type
Original Scientific Research-Oral or Pos
Authors
J An1, S Xu1, N Glossop2, A Chen1, B Wood1
Institutions
1National Institutes of Health, Bethesda, MD, 2ArciTrax Inc., Toronto, Ontario
Purpose
Intrinsic respiratory motion is a common obstacle in image guided interventional procedures. The lack of direct feedback from internal organ motion often leads to suboptimal accuracy of image guidance. In response to this problem, a new needle-like device is developed to monitor and compensate for real-time position changes.
Materials & Methods
A miniaturized electromagnetic tracking sensor is integrated with an anchoring needle prototype. The needle is equipped with four deployable prongs on the needle shaft and locking spacer on the cutaneous end. Reinforced stabilization is accomplished with a fitted, detachable disk placed after device insertion. A cow liver-model was used to validate the effectiveness of the anchoring needle. Passive and active fiducial markers were placed on the simulated skin of the apparatus as standard image guided procedures. A pre-procedural CT was obtained and used to guide needle targeting using electromagnetic tracking and custom research software. Interventional needle placement was performed on 3 artificially placed tumor targets under three different conditions: no internal motion, with simulated internal motion, and with use of position monitoring needle under motion. Spatial accuracy was defined by basic tracking error, the distance between tracked needle tip to target distance.
Results
One-way analysis of variance was used to assess difference between all three groups; one-tailed T test was used to assess the effect of the motion tracking error in the two groups with motion. Guided needle placement with no motion yielded basic tracking error of 9.10mm (σ²=39.24), basic tracking error with motion was 43.43mm (σ²=2.12), which improved to 10.60 (σ²=0.09) with tracked-internal position monitor (p<0.001). Isolated analysis in the two group with simulated respiratory motion revealed a significant improvement in basic tracking error with the use of the tracked anchoring needle (p<0.001).
Conclusions
Motion detection and position monitoring significantly improved the accuracy of procedural needle placement. Our working prototype is the first internal stabilization device on record that attempts to adjust for respiratory misregistration of tracking system in real-time.
Final ID
490
Type
Original Scientific Research-Oral or Pos
Authors
J An1, S Xu1, N Glossop2, A Chen1, B Wood1
Institutions
1National Institutes of Health, Bethesda, MD, 2ArciTrax Inc., Toronto, Ontario
Purpose
Intrinsic respiratory motion is a common obstacle in image guided interventional procedures. The lack of direct feedback from internal organ motion often leads to suboptimal accuracy of image guidance. In response to this problem, a new needle-like device is developed to monitor and compensate for real-time position changes.
Materials & Methods
A miniaturized electromagnetic tracking sensor is integrated with an anchoring needle prototype. The needle is equipped with four deployable prongs on the needle shaft and locking spacer on the cutaneous end. Reinforced stabilization is accomplished with a fitted, detachable disk placed after device insertion. A cow liver-model was used to validate the effectiveness of the anchoring needle. Passive and active fiducial markers were placed on the simulated skin of the apparatus as standard image guided procedures. A pre-procedural CT was obtained and used to guide needle targeting using electromagnetic tracking and custom research software. Interventional needle placement was performed on 3 artificially placed tumor targets under three different conditions: no internal motion, with simulated internal motion, and with use of position monitoring needle under motion. Spatial accuracy was defined by basic tracking error, the distance between tracked needle tip to target distance.
Results
One-way analysis of variance was used to assess difference between all three groups; one-tailed T test was used to assess the effect of the motion tracking error in the two groups with motion. Guided needle placement with no motion yielded basic tracking error of 9.10mm (σ²=39.24), basic tracking error with motion was 43.43mm (σ²=2.12), which improved to 10.60 (σ²=0.09) with tracked-internal position monitor (p<0.001). Isolated analysis in the two group with simulated respiratory motion revealed a significant improvement in basic tracking error with the use of the tracked anchoring needle (p<0.001).
Conclusions
Motion detection and position monitoring significantly improved the accuracy of procedural needle placement. Our working prototype is the first internal stabilization device on record that attempts to adjust for respiratory misregistration of tracking system in real-time.