The HALO90 System is designed for coagulation of sites in the gastrointestinal tract, including the treatment of Barrett's esophagus. Barrett's is a pre-cancerous condition of the esophagus often caused by gastroesophageal reflux disease. The HALO90 System is can be used independently or in conjunction with the commercially available HALO360 System, a balloon-based endoscopic ablation system for treating larger, circumferential areas of Barrett's esophagus. Both products are based on patented technology that carefully controls the amount of energy delivered to the tissue so as to safely and effectively remove the diseased tissue and facilitate the re-growth of new healthy tissue. Together, the products offer physicians a safe and convenient solution for the complete removal of Barrett's esophagus.