The influence of different processing methods on the quality of 18F-FDG PET whole body images

Objective: The aims of this study was to evaluate the influence of different reconstruction methods on the quality of 18F-fluorodeoxyglucose (FDG) PET whole body images and was to select a good reconstruction method. Methods: 18F-FDG whole body scanning was performed on 5 normal subjects and 5 patients with known malignancy. The raw data of each one were reconstructed with different reconstruction methods, including ordered subsets-expectation maximization (OSEM) reconstruction, attenuation-corrected and non-corrected back-projected filter reconstruction. The influence of different smooth methods, such as Non-quantitative and Gaussian, on the image quality was also evaluated. Results: In non-corrected images, the central tissue of the body was displayed un-clearly because of radioactivity attenuation. Some other shortcomings such as distortion of lesions, artifacts, difficult position of lesions and incapableness of standard uptake value (SUV) measurement were also seen. The image quality was poor. In corrected images, some shortcomings such as the central tissues displayed, the lesion position and the disadvantages of measurement of SUV were overcomed, but the quality of images was still poor because of a lot of artifacts. With OSEM reconstruction, the image quality was improved very greatly. Artifacts were fewer. The central tissues were displayed clearly, and the position of lesion and measurement of SUV were also easy and precise. When reconstructed with backproject filter, the influence of smooth methods on image quality was great and the non-quantitative method was better than Gaussian. When reconstructed with OSEM, the influence of smooth methods on the image quality was little and Gaussian was better slightly. Conclusions: The quality of 18F-FDG whole body images was influenced by the reconstruction method greatly. With corrected OSEM reconstruction and Gaussian smooth method, the perfect images could be obtained