In-situ, real-time monitoring of thermo-mechanical properties of biological tissues undergoing laser heating and ablation.

In this work, Brillouin light-scattering spectroscopy and optical backscattering reflectometry (OBR) using Mg-silica-NP-doped distributed sensing fibers were employed for monitoring local GHz visco-elastic properties and surface temperature, respectively, laser driven heating and ablation of chicken tissues. The spatial temperature distribution measured by OBR at various infrared laser heating powers and times was used to validate spatio-temporal local temperature variations modeled by the finite element method via solving Pennes' bioheat conduction equation. The reduction of viscosity and stiffness in chicken skin during its laser heating was attributed to water loss, protein denaturation and change in lipid phase behavior. These findings open avenues for the simultaneous real-time hybrid optical sensing of both viscoelasticity and local temperature in biological tissues undergoing denaturation and gelation during thermal ablation in clinical settings.