We aimed to evaluate the influence of noise and object size on segmentation accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. The scanned data of spherical phantoms were used. For the gradient method, 40% maximum standardized uptake value (SUVmax) method, and SUV of 2.5 threshold method, we evaluated the correlation between segmentation accuracy and background variability and that between segmentation accuracy and sphere diameters. For the gradient method, background variability did not affect segmentation accuracy, but sphere diameters had a small effect. As for the 40% SUVmax threshold method, both sphere diameters and background variability affected the segmentation accuracy. In the SUV of 2.5 threshold method, segmentation accuracy was affected by sphere diameters but not by background variability. With regard to segmentation accuracy of FDG-PET imaging, the gradient method may be more accurate and reliable compared to threshold methods when applied to images with varying noise or object size.
Keywords: FDG-PET; Gradient method; SUVmax; Segmentation.