In this report, we propose to reconstruct thermal properties such as thermal conductivity and thermal diffusivity in addition to the mechanical properties for diagnosis and treatment (planning). Temperature distribution can be measured by ultrasonic imaging and MRI. Provided that the reference values of thermal properties are given in the ROI as initial conditions, by solving the simultaneous first order partial differential equations (PDEs) having the temperature distributions as inhomogeneous coefficients, we can determine the thermal property distributions. Simulations and phantom experiments were conducted.