Real-time distributed optical fiber system for simultaneous temperature and viscoelasticity monitoring during laser ablation in biological tissues enabled by nanoparticle-doped fibers

Laser ablation is an emerging technique for precise surgical interventions, especially in oncology, where localized heating is employed to destroy malignant tissues. However, real-time monitoring of both temperature and mechanical properties of tissues during the ablation procedure is critical for ensuring efficacy and safety of treatment. This research introduces a unique approach for real-time monitoring of temperature and viscoelastic properties in biological tissues during laser ablation. Our system utilizes Optical Backscatter Reflectometry (OBR) and Nanoparticles-doped fibers (NPDFs), leveraging the Scattering-Level Multiplexing (SLMux) technique. The system operates on the basis of 10 cm length of 4 NPDFs parallelly positioned along the surface of chicken samples. This configuration resulted in a highresolution 2D temperature sensing map based on distributed fiber optic technology with a resolution of 2 mm by 5 mm, covering an area of 60 mm by 15 mm with a total of 124 sensing points. The measurements were validated by performing laser ablation on the chicken samples for 1 hour at certain power levels. Simultaneously Brillouin Light Scattering (BLS) measurements were conducted every 10 minutes to assess the viscoelastic properties of the tissues. The temperature distribution during the ablation was continuously monitored, providing precise and detailed mapping of the ablation zones. The results demonstrate the capability of the system to accurately monitor temperature fluctuations and viscoelastic c property changes to correctly control the thermal dosimetry and the mortality rate of cells. The possibility of OBR combined with NPDFs and the SLMux technique provides spatially resolved profile of hyperthermal therapy in a real-time mode. This enhancement maximizes the efficiency of laser ablation treatments and minimizes unintended harm, hence improving the safety and effectiveness of thermal therapy in medicine. It specifically benefits the treatment of surface-level cancers such as skin and bladder cancer in the field of oncology.