Image-guided dynamic laser coagulation using a double-clad fiber-based system (Conference Presentation)

Abstract

Optical coherence tomography (OCT) used in combination with laser coagulation to mark selected regions of interest could efficiently guide the collection of biopsies. This would reduce false-negative findings, and have a significant impact on the management of Barrett’s esophagus. Here, we present a system based on double-clad fiber (DCF) capable of delivering marking laser light through the inner cladding while performing OCT through the core. A previously clinically validated commercial OCT system (NVisionVLE, Ninepoint Medical) was adapted in order to perform in vivo esophageal image-guided dynamic laser marking. A dedicated DCF coupler (core signal transmission: ~95%; inner cladding coupling: ~75%) was implemented into the system to combine both modalities into the DCF. The original rotary junction, necessary for helical scanning with a side-looking fiber probe, was replaced by a custom DCF-based optical rotary junction (Princetel Inc.). This rotary junction was optimized to provide low insertion loss and crosstalk to preserve imaging quality (effective dynamic range of up to 52dB). DCF-based OCT catheters were designed to have a beam waist diameter of 62±4µm at a working distance of 9.3±0.4mm, for use with a 17-mm diameter balloon sheath. Our previous ex vivo marking experiments demonstrate that, based on the characterization of these DCF components, the system is capable of single-pulse laser marking at 1436 nm. This enables further in vivo experiments to demonstrate image-guided dynamic laser marking and potentially other therapeutic applications. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.