Miniaturized mechanical design of a spiral-scanning laser ablation instrument for advanced surgical applications

Picosecond-pulsed lasers offer a method for removing neoplastic tissue with minimal damage to adjacent structures. Their ability to precisely ablate pathological regions with micron-level accuracy is valuable, especially in anatomically constrained environments. However, limited physical access remains a major challenge and restricts broader clinical integration. Improving device maneuverability is therefore essential for advancing this technology. Our previous prototype introduced a spiral-scanning approach for distributing laser energy. The present work expands on that design. The new probe has a compact form, measuring 12 mm in diameter and 300 mm in length, making it suitable for both endoscopic and laparoscopic procedures. One of the main innovations is the distal scanning tip, intended to produce Archimedean spiral patterns. This ensures the laser energy spreads uniformly over the target area. The device can achieve a laser spot diameter of 20 microns and is able to scan a 0.6 mm radius area in approximately 90 seconds by following a spiral trajectory at a speed of 2 mm/s. However, there are several key engineering challenges, such as mechanical miniaturization, ensuring the perpendicularly emitted laser from the probe surface during scanning, and stability of the fiber-attached tip during rapid spiral scan. Overcoming these obstacles substantially improved the performance and reliability of using this probe for clinical applications. Conducted experiments demonstrated that our new probe showed superior performance. It can generate consistently tight, densely packed spiral patterns with high scanning performance, covering almost the entire target area with minimal unscanned regions. In addition, real-time imaging during the experiment setups showed that the laser spot traveled at a constant velocity of about 2 mm/s along an Archimedean spiral. Preliminary results indicate notable improvements in scanning sensitivity, speed, and coverage compared to our initial prototype. These advancements suggest strong potential for a wide range of clinical applications.