Differences in image quality of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) can affect lesion detectability on acquired images. The authors describe a 26-year-old woman with a history of Hodgkin’s disease whose residual tumor was not detected initially after dose infiltration and imaging acquisition 60 minutes after injection at a glucose level of 106 mg/dl. The residual tumor was detected 2 weeks later after F-18 FDG injection via a central venous access line, to avoid dose infiltration, and imaging performed 90 minutes after injection at a glucose level of 82 mg/dl. This case demonstrates various parameters, such as injection dose, postinjection scan delay, and blood glucose level, that can affect FDG-PET image quality and lesion detectability as a result.