In onclogical imaging the goals are lesion detection and localization ,lesion characterization ,proper staging ,and treatment success.some of these goals require precise anatomical imaging .It was therefore,easily acknowledged that FDG-PET and CT are complementary ,and the employment of the two is imperative in the oncological clinical practice. By recognizing the relevant radiologic and behaviour of chest tumors,understanding the appropriatness of staging disease wiyh TNM classification system, and being familiar with potential imaging pitfalls,PET/CT can make an important contribution to diagnosis,treatment and outcom in chest tumor patients