Analytical methods for solving heat distributions and estimating transient pressures in laser-irradiated biological tissue (Conference Presentation)

The complexity of biological tissue poses a significant challenge for modeling laser-tissue interactions. Successful analytical methods for determining heat distributions due to low-energy irradiation exist, yet all assume a homogeneous medium. Because a medium's response is driven by the spatial gradient of the temperature distribution, steady-state and transient pressures are inaccurate. This work proposes a heat distribution that estimates differences in optical absorption within biological tissue, and Green's function is used to solve the heat equation. An exact solution is defined by assuming that the size of the optical differences is much less than the beam width or optical attenuation coefficient. The use of generalized thermoelasticity reveals that the degree and size of tissue heterogeneity significantly impact the generation of quasistatic and transient pressures. Solving the heat equation in this form is a powerful tool for understanding pressures generated in laser-irradiated tissue, which could benefit studies of mechanotransduction, photoacoustic tomography, and laser therapy modeling.