FDG imaging of lung nodules: A phantom study comparing SPECT, camera-basedPET, and dedicated PET

PURPOSE: To evaluate 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) imaging of simulated lung nodules in a realistic chest phantom by using attenuation -corrected and non-attenuation-corrected 511-keV single photon emission com puted tomography (SPECT), camera-based positron emission tomography (PET), and dedicated PET imaging. MATERIALS AND METHODS: Spheres with diameters of 6, 10, 13, and 22 mm were placed in the lungs of an anthropomorphic chest phantom to simulate nodules . The lungs, nodules, chest wall, and mediastinum were filled with fluorine -18 activities based on the average radionuclide concentrations in those st ructures from analysis of attenuation-corrected dedicated FDG PET scans. Th e image sets were evaluated visually and quantitatively by using contrast a nd signal-to-noise ratios. RESULTS: Attenuation correction reduced the artificially high apparent upta ke in the lungs, restored the spherical shape to the nodules, and provided an accurate outer body contour with appropriate intensity. Dedicated PET de picted all four nodules, camera-based PET depicted the three largest nodule s, and SPECT depicted the two largest nodules. Lesion contrast was better o n the attenuation-corrected images than on the non-attenuation-corrected im ages. The signal-to-noise ratio generally was improved with attenuation cor rection. CONCLUSION: Attenuation correction results in many changes in the images an d improves lesion detection.