Experimental evaluation of thermal effect of circumferentially emitted laser in an in-vivo rabbit esophageal model

Barrett’s esophagus (BE) is a premalignant condition in which the normal squamous epithelium of the distal esophagus is replaced by columnar epithelium due to chronic acid reflux. BE is associated with esophageal adenocarcinoma, the eighth most common cancer worldwide. Current ablative treatments, including radiofrequency ablation (RFA), argon plasma coagulation (APC), and laser ablation, face limitations such as nonuniform energy delivery and uncontrolled thermal injury. These limitations may cause adverse effects, including bleeding, perforation, or organ narrowing. Consequently, achieving effective eradication of abnormal tissue while preserving deeper healthy layers remains a critical challenge. In this study, we investigate the in vivo performance of a new-generation endoscopic cap designed for circumferential laser coagulation using a radial optical fiber. A vacuum-assisted prototype system was evaluated in a rabbit esophagus model. The radial fiber delivered 1540 nm laser light circumferentially to the tubular esophageal tissue, while vacuum suction pulled the mucosal layer into a recessed ablation channel, ensuring consistent tissue contact and controlled treatment depth. Laser irradiation was applied at a fixed esophageal location using power levels of 0.9–1.8 W and exposure durations of 2.5, 5, and 10 s. Negative pressure was varied from 100 to 300 mmHg to assess potential mechanical damage to tissue. Laser-induced thermal effects were assessed by histological analysis of esophageal tissue collected immediately and six hours after in vivo experiments.