Chemotherapy-induced neurotoxicity and cognitive impairment also known as chemo-brain is a known fact in adults. However clinical data is scarce in the pediatric population. The aim of this study is to show chemotherapy related cerebral metabolic changes in pediatric lymphoma patients and create a proof of concept to plan a prospective study. Materials and Methods: Pediatric patients, diagnosed with lymphoma, undergoing FDG PET-CT scan for staging, interim evaluation and after completion of therapy composed the study group. The brain images on PET-CT scan were evaluated via statistical parametric mapping (SPM) analysis region by region, retrospectively. Images of the staging scan were accepted as a baseline and were compared with the same patient’s interim and treatment response scans. Results: A total of 87 PET-CT scans of 29 patients (12 female, 17 male) were analyzed visually and semiquantitatively, for this preliminary work. A significant increase of FDG brain uptake in the cortices of the primary visual (+0.17 for left p=0.001 and +0.18 for right p<0.001), occipital lateral (+0.1 for left p=0.002 and 0.17 for right p=0.003), precuneus (+0.06 for p=0.06 and +0.06 for right p=0.03), sensorimotor (+0.06 for right p=0.04) and parietal

inferior (+0.5 for left p=0.6) was observed compared to the basal status. Conclusion: Cognitive decline in oncology patients under chemotherapy is under research by most disciplines. We presume FDG PET scan in the pediatric population may give an opportunity to the related clinicians in advance for early intervention. This study revealed the further need of prospective trials that combined with neurocognitive performance tests.