Purpose: Tc-99m-3PRGD2, a promising tracer targeting integrin receptor, may serve as a novel tumor-specific agent for single photon emission computed tomography (SPECT). A multi-center study was prospectively designed to evaluate the diagnostic accuracy of Tc-99m-3PRGD2 imaging for bone metastasis in patients with lung cancer in comparison with the conventional Tc-99m-MDP bone scan. Methods: The patients underwent whole-body scan and chest tomography successively at both 1 h and 4 h after intravenous injection of 11.1 MBq/Kg Tc-99m-3PRGD2. Tc-99m-MDP whole-body bone scan was routinely performed within 1 week for comparison. Three experienced nuclear medicine physicians blindly read the Tc-99m-3PRGD2 and Tc-99m-MDP images. The final diagnosis was established based on the comprehensive assessment of all available data. Results: A total of 44 patients (29 male, 59 +/- 10 years old) with suspected lung cancer were recruited from 4 centers. Eighty-nine bone lesions in 18 patients were diagnosed as metastases and 23 bone lesions in 9 patients were benign. In a lesion-based analysis, Tc-99m-3PRGD2 imaging demonstrated a sensitivity, specificity, and accuracy of 92.1%, 91.3%, and 92.0%, respectively. The corresponding diagnostic values for Tc-99m-MDP bone scan were 87.6%, 60.9%, and 82.1%, respectively in the same patients. Tc-99m-MDP bone scan had better contrast in most lesions, whereas the Tc-99m-3PRGD2 imaging seemed to be more effective to exclude pseudo-positive lesions and detect bone metastases without osteogenesis. Conclusion: Tc-99m-3PRGD2 is a novel tumor-specific agent based on SPECT technology with a promising value in diagnosis of bone metastasis in patients with lung cancer.