Study to optimize VMAT plan in treatment of head and neck cancer by using 6 MV FF and FFF photon beams

This study aims to compare and evaluate the dose distribution and physical characteristics of photon beams 6 MV Flattening Filter (FF) and 6 MV Flattening Filter Free (FFF) of TrueBeam STx (FFF) in Eclipse v13.6 software in head and neck cancer (H&N) treatment plans.