A 31-year-old woman who underwent 2 phases of chemotherapy for Hodgkin lymphoma subsequently underwent 8 F-FDG PET/CT scans for staging and treatment response evaluation. The images revealed that the Hounsfield unit and SUV of the thymus changed with the therapeutic status; both decreased to the lowest level 0.5 months after chemotherapy and increased to the highest level 8 to 12 months after the end of treatment. Interestingly, we found a positive correlation between the thymic Hounsfield unit and SUV, with a Spearman correlation coefficient of 0.946 (P < 0.001).