Superficial photothermal laser ablation of ex vivo sheep esophagus using a cone‐shaped optical fiber tip

Abstract

Superficial photothermal laser ablation (SPLA) may be useful as a therapeutic approach producing a depth of injury that is sufficient to eliminate mucosal lesion but not deep enough to induce thermal effects in deeper tissue layers. The purpose of this preliminary study is twofold: (a) to describe design steps of a fiber probe capable of delivering a tightly focused laser beam, including Monte-Carlobased simulations, and (b) to complete the initial testing of the probe in a sheep esophagus model, ex vivo. The cone-shaped (tapered) fiber tip was obtained by chemical etching of the optical fiber. A 1505 nm diode laser providing power up to 500 mW was operated in continuous wave. The successful SPLA of the sheep mucosa layer was demonstrated for various speed-power combinations, including 300 mW laser power at a surface scanning rate of 0.5 mm/s and 450 mW laser power at a surface scanning rate of 2.0 mm/s. Upon further development, this probe may be useful for endoscopic photothermal laser ablation of the mucosa layer using relatively low laser power. K E Y W O R D S chemical etching, fiber probe, Monte Carlo, mucosa, photothermal ablation

Multifunctional Ablative Gastrointestinal Imaging Capsule (MAGIC) for Esophagus Surveillance and Interventions

“…Subsequent treatment with the integrated ablation laser could be conducted, selectively targeting well-defined areas of abnormal superficial tissue and minimizing damage to the adjacent or deeper healthy tissues. Unlike traditional fiber-optic-based laser ablation, which frequently demands multiple sessions [ 41 ], the MAGIC provides 3D scanning capabilities (circumferential and pullback). It could facilitate the ablation of as extensive area akin to conventional radiofrequency ablation, while the depth of tissue ablation can be more precisely controlled [ 42 ].…”