The purpose of the study was to evaluate the performance of dual-head coincidence gamma camera imaging using FDG in association with serum marker assays in identifying lung carcinoma in patients with abnormal findings on chest radiography. Methods: A prospective evaluation of FDG imaging with coincidence detection emission tomography (CDET) using a dual-head gamma camera combined with the assessment of 3 sensitive serum markers of lung cancer (carcinoembryonic antigen, neuron specific enolase, and CYFRA 21-1) was performed on the same day on 58 consecutive patients with known or suspected lung malignancy. Results: Fifty-three patients were proven to have lung cancer, and 5 patients had benign lung disease. Coincidence imaging showed significantly increased FDG uptake in 49 of 53 patients with proven malignancy (sensitivity, 92.5%) and in 3 patients with benign disease. FDG imaging had negative findings in 4 patients with proven malignancy and 2 patients with benign disease. Serum tumor marker levels were elevated in 42 of 53 cancer patients (sensitivity, 79.2%) and normal in 11 patients with proven malignancy. Nine patients with proven malignancy had positive findings on FDG images and negative marker assays. Two patients with proven malignancy had negative findings on FDG images and positive marker assays. The positive predictive value for lung cancer was 94.2% for FDG alone and 97.6% for FDG in association with serum markers. Conclusion: In this study, FDG CDET imaging was a powerful tool for evaluating patients with lung lesions suggestive of malignancy. Although the determination of serum marker levels was less accurate than FDG imaging, positive FDG results found in association with positive markers significantly increased the likelihood of lung malignancy.