Background: Differentiating true progression (TP) from treatment-related changes (TRC) after radiation therapy in glioma patients remains a major diagnostic challenge. While MRI is the standard follow-up modality, its specificity is limited in this context. Amino acid PET imaging with [18F]FDOPA has shown promise in improving diagnostic accuracy. Case Presentation: A 43-year-old man with previously treated IDH-mutant Grade 3 astrocytoma presented with new contrast enhancement on MRI, raising suspicion for recurrence. Static [18F]FDOPA PET imaging revealed elevated uptake (tumor-to-background ratio, TBRmax = 2.5), while dynamic analysis showed an early peak at 8 minutes and a washout pattern, supporting a diagnosis of TP. Subsequent imaging confirmed lesion progression, accompanied by clinical deterioration. Discussion: This case illustrates the added diagnostic value of dynamic [18F]FDOPA PET imaging in differentiating TP from TRC in IDH-mutant gliomas. Dynamic PET parameters, such as time-to-peak and washout slope, enhance interpretation beyond static uptake measures, especially in equivocal MRI findings. While prior studies have emphasized dynamic [18F]FET PET, emerging evidence supports similar utility for [18F]FDOPA, with shorter acquisition times and promising accuracy, particularly when stratifying by molecular subtype. Conclusion: Dynamic [18F]FDOPA PET imaging is a valuable adjunct to MRI in the post-treatment assessment of gliomas, offering enhanced diagnostic confidence and informing clinical decision-making, particularly in complex IDH-mutant cases.