Lung cancer is the cause of 32% of all male cancer deaths and 25% of all female cancer deaths. Because the prognosis depends on early diagnosis and staging, continuous evaluation of the diagnostic tools available is important. The aim of this study was to assess the diagnostic value of dedicated positron emission tomography (PET) and gamma-camera PET in the diagnostic investigation of non-small-cell lung cancer (NSCLC). A systematic literature search was carried out in the MEDLINE and EMBASE databases and the Cochrane Controlled Trials Register. We identified 55 original works on the diagnostic performance of PET with fluorodeoxyglucose in the investigation of NSCLC. For diagnosis of NSCLC, the mean sensitivities and specificities were, respectively, 0.96 (SE 0.01) and 0.78 (0.03) for dedicated PET, and 0.92 (0.04) and 0.86 (0.04) for gamma-camera PET. In the mediastinal staging of NSCLC, the results were 0.83 (0.02) and 0.96 (0.01) for dedicated PET and 0.81 (0.04) and 0.95 (0.02) for ganuna-camera PET. We conclude that dedicated PET could be a valuable tool in the diagnosis and staging of NSCLC. However, studies of populations with a lower prevalence of NSCLC are recommended.