A Modular Endoscopic Tool and Laser Ablation Test-Bed for Studying Biological Tissue Ablation Control Strategies

Robotized laser endoscopic tools provided surgeons with increased accuracy for ablating tissue. Here, a new modular endoscopic laser scanner system test-bed was designed and fabricated for conducting experiments into control strategies. This new system used a continuous wave (CW) laser system specifically designed for the task. Experiments into biological tissue ablation with this new system were compared with experiments previously conducted using a pulsed laser system. The torque required to accurately position the light beam of the flexible fiber optic cable was derived by solving Maxwell’s equations. The new test-bed again included a photo-detector sensor, which was used to position the laser beam on the tissue and provide closed-loop feedback control. With this arrangement, laser beam tracking errors were shown to be smaller than in the original pulsed laser experiments, and the tissue ablation patterns were repeatable. Trials on biological tissue (chicken meat) with this new physical test-bed proved that the tissue ablation pattern experiments were consistent, robust, and accurate. A COMSOL simulation of heat propagation then showed that consistency between the experimental and the simulation results. It also gave indicators for additional test-bed design changes that are required for optimizing the control of laser beam/biological tissue ablation.