An endoscopy capsule for well-confined and angle-controlled photothermal mucosa ablation

Abstract

As the innermost layer of the gastrointestinal (GI) tract, the mucosa layer has critical importance in carcinogenesis. Barrett’s esophagus is a pre-cancerous lesion characterized by intestinal metaplasia within the stratified squamous epithelium of esophageal mucosa. Mucosal lesions that are not adequately treated tend to enlarge and become cancerous tissue over the surface and deeper layers. Although various treatment strategies are available, uncontrolled depth of treatment to eliminate lesions is still challenging. Exceeding the treatment depth may cause adverse effects on the underlying healthy tissue layers, while insufficient treatment depth may cause the lesion to recur. Besides, the inhomogeneity of the distribution of the lesions on the esophageal surface makes it difficult to apply ablation therapy in a single session, requiring more sessions. However, a feasible approach is still needed to perform the desired results in photothermal ablation at a single therapy session. This study demonstrates an endoscopy capsule that provides well confined and angle-controlled photothermal mucosal ablation. The capsule consists of three parts: a base that holds a stepper motor and a GRIN lens; a cap that includes gold-coated right-angle prism mirrors; an optically transparent and perforated body for negative pressure unites the base and cap. The mucosa layer is confined to the recessed area of the capsule by negative pressure delivered through holes. The laser beam at 1505 nm is rotated with a constant speed and defined rotation angles for circumferential photothermal ablation.