  A new model is considered to describe the evolution of tissue temperature and
water concentration during a thermal ablation process. The aim of this study is
to expand the results obtained in Blauth et. al. 2020, where the tissue water
concentration is considered as a known function, experimentally obtained.
  The model consists of two coupled equations: a parabolic partial differential
equation for the temperature $\theta$ and an ordinary differential equation for
the water content $w$.
  The equation for $\theta$ accounts for temperature diffusion, blood
perfusion, the heat source provided by the laser applicator and the
vaporization effects which act when the temperature approaches 100C. The
equation for $w$ accounts for the loss of tissue water that occurs during
vaporization.
  The model equations are solved in a cylindrical domain around the laser
applicator and the results are compared with the existing experimental data for
porcine liver tissue from H\"ubner et. al. 2017.
