FDG imaging of lung nodules: a phantom study comparing SPECT, camera-based PET, and dedicated PET.
OBJECTIVE
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 computed tomography (SPECT), camera-based positron emission tomography (PET), and dedicated PET imaging.


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 structures from analysis of attenuation-corrected dedicated FDG PET scans. The image sets were evaluated visually and quantitatively by using contrast and signal-to-noise ratios.


RESULTS
Attenuation correction reduced the artificially high apparent uptake in the lungs, restored the spherical shape to the nodules, and provided an accurate outer body contour with appropriate intensity. Dedicated PET depicted all four nodules, camera-based PET depicted the three largest nodules, and SPECT depicted the two largest nodules. Lesion contrast was better on the attenuation-corrected images than on the non-attenuation-corrected images. The signal-to-noise ratio generally was improved with attenuation correction.


CONCLUSIONS
Attenuation correction results in many changes in the images and improves lesion detection.
Coleman
R E
RE
Department of Radiology, Duke University Medical Center, Duke Hospital North, Durham, NC 27710, USA.
Laymon
C M
CM
Turkington
T G
TG
D019788:Fluorodeoxyglucose F18; D015902:Gamma Cameras; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008482:Mediastinum / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals; D012815:Signal Processing, Computer-Assisted; D013909:Thorax / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed / Q000295:instrumentation / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18