Because it is absolutely inert in the human body, immune to attack from bodily fluids, compatible with bone growth, and strong and flexible, titanium is the most biocompatible of all metals. The purpose of this study was to investigate the dosimetric effect of various cerebral implant Titanium plate thickness (0.05-1.cm) irradiated by 4 MV photon beam using Monte Carlo (Fluka). The simulations result shows that increasing thicknesses of the Ti plate rise the dose deposition near to plate. Also the dose deposition is varying when the Ti plate is set in different depth from the surface of the water equivalent phantom (for example the dose deposition decrease about 8% for 1cm). The second part of this study is dedicate to investigate the effect of scattered radiation produced in a cerebral implant for various materials including Ti alloys such as Ti-6Al-7Nb, Ti-6Al-4V(α) and Ti-6Al-4V(β).Index Terms-bacscatted gamma, dose distributions, FLUKA simulation, Titanium alloys plate I.