Feasibility study of endoscopic thermal coagulation with circumferential laser irradiation for treating esophageal tissue.

Barrett's esophagus (BE) is associated with an intestinal metaplasia that replaces normal squamous epithelium by columnar epithelium. The aim of the current study was to evaluate the feasible endoscopic treatment on esophageal tissue with circumferential laser irradiation. A 532-nm laser was used to deliver 10 W in a continuous manner through a balloon catheter-integrated diffuser. Ex vivo leporine esophagus was tested to identify thermal responses at various irradiation times. In vivo testing in a porcine model was performed to evaluate the feasibility of endoscopic application with the integrated device for BE treatment. Goniometric measurements confirmed that the proposed device yielded uniform radial irradiation (i.e., 0.9 ± 0.1 in arbitrary unit). Emission profiles were well correlated with temperature distribution along the device. Ex vivo leporine testing demonstrated that the temperature rise increased with irradiation time. The maximum temperature increase was around 38 °C after 60-s irradiation (transient increase rate = 0.62 °C/s), and the corresponding thermal coagulation reached esophageal submucosa (1.5 ± 0.2 mm). In vivo porcine testing evidently presented circumferential thermal denaturation around the lumen along with mild inflammatory reaction and the degenerated squamous epithelium. The overall thickness of the irreversible thermal coagulation was 3.1 ± 0.2 mm. The proposed photothermal therapy can be a feasible endoscopic method to treat BE with the aid of circumferential irradiation and mechanical expansion. Further chronic in vivo testing will be pursued to understand chronic tissue response in terms of wound healing and complication.