PURPOSE: The purposes of our study were to assess the dual blood supply of lung cancer using a computed tomography (CT) perfusion technique, and to analyze the correlations between dual perfusion and various characteristics of lung cancer. MATERIALS AND METHODS: Thirty-five consecutive patients with lung tumors highly suggestive of malignancy were included in this study. All subjects underwent a dual-input dynamic perfusion volume scan using a 320-detector-row CT before CT-guided biopsy. The pulmonary trunk and the descending thoracic aorta were selected for the arterial input functions. From the CT data, pulmonary arterial perfusion (PP), aortic perfusion (AP), and the perfusion index [PI = PP / (PP + AP)] were calculated using the dual-input maximum-slope method. We statistically analyzed the relationship of the perfusion data with tumor locations (central, peripheral, and abutting the pleural lesions), tumor volumes, and the presence of lymph node metastasis or distant metastasis. RESULTS: All subjects were pathologically diagnosed with primary lung cancers via CT-guided aspiration biopsy. The overall mean PI was 53.7 ± 7.2%. The PI showed a significant difference according to the tumor location (central, 49.2 ± 3.3%; peripheral, 56.2 ± 6.7%; abutting the pleural lesions, 48.9 ± 7.6%, p = 0.047). In contrast, no significant difference was detected in tumor size or the presence of metastasis (p > 0.05). CONCLUSION: We found that the proportion of dual perfusion in lung cancer was significantly dependent on the location of the tumor, while tumor size or the presence of metastasis was not distinctly associated with dual perfusion.