In this paper, we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three-dimensional (3D) Finite Element Method (FEM) simulations of the heating of the human head induced by cell phone. In particular, we utilize the Pennes equation to describe the bioheat transfer with the right hand side representing the heat generated by cell phone. We utilize our own non-stationary time dependent multi-thread parallel direct solver for the solution of this computational problem. From our numerical results it follows that 15 minutes (1000 seconds) exposure to the cell phone radiation implies up to 2 degrees Celsius increase of the temperature of the brain in the range close to the cell phone.