Towards a smart delivery probe for endo-venous laser ablation

Endo-venous laser ablation (EVLA) is emerging as one of most important minimally invasive procedures for treating varicose veins, offering reduced patient discomfort compared to traditional methods. The procedure uses a laser beam to collapse and induce sclerosis in vein walls, effectively sealing the vein. Among the various medical wavelengths, recent advancements favor the use of 1900 nm lasers, particularly those based on thulium-doped fiber technology, due to their highly localized heating effects. However, discrepancies in the literature regarding the optimal laser irradiation dose highlight the need for an applicator that integrates temperature sensors to provide the surgeon with real-time feedback. As a preliminary work the paper discusses the use of fiber Bragg gratings to measure the temperature distribution induced by two lasers emitting at the opposite edges of the commonly used therapeutic wavelength range. For easiness and better reproducibility, the tests have been carried out on egg white phantoms, simulating vascular veins; the results demonstrate that heating at 1900 nm outperforms that at 975 nm by minimizing spurious temperature increases outside the target volume. Additionally, the experiments emphasize the importance of carefully tuning laser power to prevent carbonization. The outcomes of the ablation tests are in good agreement with those found in clinical trials, thus demonstrating promising capabilities of this novel applicator.