PURPOSE: An anchored Beacon(r) transponder with a 5-legged anchoring feature and dedicated delivery catheter was developed for use with an electromagnetic, real-time tracking system (The Calypso(r) System, Calypso Medical Technologies, Inc., Seattle, WA). The anchored transponder will enable targeted radiation therapy of the lung and address challenges associated with other fiducial based localization techniques. We assessed the performance of the delivery catheter to place anchored transponders in cadaveric human lungs.
METHODS: Three cadaveric human torsos (Science Care, Phoenix, AZ) with bilateral chest tubes in the pleural space were used. The trachea was intubated and connected to a constant 30 cm H2O pressure source. Five simulated tumors were made per torso. Computed tomography was performed and the 3 best-circumscribed targets in each torso were chosen. Three experienced bronchoscopists each reviewed the CT images of one torso and chose 3 anchored transponder target implantation sites near each of the 3 simulated tumors. Bronchoscopic implantation was guided by fluoroscopy alone for 4 implantations or electromagnetic navigation (inReach(tm), superDimension, Inc., Minneapolis, MN) and fluoroscopy for 5 implantations. Operator assessment of catheter function was assessed using a 5-point scale; 5 reflecting "very easy". Implantation time was recorded. Computed tomography was repeated to assess implantation accuracy.
RESULTS: All 27 (100%) of the anchored transponders were successfully implanted. The mean operator-assessed score for ease of passage through the bronchoscope or extended working channel as 4.9 and ease of deployment as 4.9. The mean time to implant a single anchored transponder was 4.2 minutes (range 1-16). The mean distance between the implanted transponders and the edge of the targets was 1.2 cm.
CONCLUSION: Bronchoscopic implantation of anchored transponders using this novel dedicated delivery catheter was successful 100% of the time. Operator satisfaction with the performance of the delivery catheter was very high. Average implantation time was only 4.2 minutes per anchored transponder.
CLINICAL IMPLICATIONS: Use of this delivery catheter enables "very easy" placement of anchored transponders in human lungs near simulated tumor targets.
DISCLOSURE: Jed Gorden, Grant monies (from industry related sources) Ryan L Smith receives support from a grant from Calypso Medical Technologies administered by Washington University; Consultant fee, speaker bureau, advisory committee, etc. Martin L Mayse is a consultant for Calypso Medical Technologies.; Product/procedure/technique that is considered research and is NOT yet approved for any purpose. The Anchored Beacon Transponder and Delivery Catheter are experimental and not available for sale.