Indwelling Stent Embedded with Light-Emitting Diodes for Photodynamic Therapy of Malignant Biliary Obstruction.

PURPOSE: We describe the design and preliminary characterization of a stent incorporating light-emitting diodes (LEDs) for photodynamic therapy (PDT) of malignant biliary obstruction. METHODS: A prototype was constructed with red (640 nm) LEDs embedded in a 14.5 French polyurethane tube. The device was evaluated for optical power and subjected to physical and electrical tests. PDT-induced reactive oxygen species were imaged in a gel phantom. RESULTS: The stent functioned at a 2.5-cm bend radius and illuminated for 6 months in saline. No stray currents were detected, and it was cool after 30 minutes of operation. Optical power of 5-15 mW is applicable to PDT. Imaging of a reactive oxygen indicator showed LED-stent activation of photosensitizer. CONCLUSIONS: The results motivate biological testing and design optimization.