This proposal is an interdisciplinary research action. The objective of the CLEAN project is to develop a novel endoscopic capsule design and to build a prototype endoscopy system using this capsule, which provides local ablation to the superficial layer of target mucosal tissue with sufficient depth to remove abnormal tissue. However, this depth will be shallow enough to avoid the residual effects of therapy within deeper tissue layers. The specific aims are: Aim-1: To develop a computer modelling to mimic the thermal dynamics of the capsule. It is to characterize the total heat energy needed to successfully ablate the lining layer, an adequate sliding speed along the oesophagus, an adequate therapy time for effective thermal target layer ablation, and the amount of thermal injury induced to the various oesophagus layers. Aim-2: To develop the configuration of the capsule in a computer-aided design program. This original design simply extends the target layer above and away from its underlying layers to achieve a well-confined therapeutic effect by delivering vacuum force. With the confinement of therapeutic effect, it is aimed that deeper tissue structures are partially separated from ablation region. Aim-3: To construct and optimize a prototype-level endoscopy system for pre-clinical ex-vivo tissue trials. A high power, 1380-nm diode laser will be used for the therapeutic photothermal ablation. Aim-4: To investigate the feasibility of the design and to evaluate the performance of the prototype system in ex-vivo sheep oesophagus model. Tissue samples will be collected for histology examination to validate the performance goals of the device.