Pitfalls and artifacts in [18F]-FDG PET imaging in children with lymphoma

: Positron emission tomography/computed tomography (PET/CT) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose ([18F]-FDG) is a well-established imaging tool in adult oncology and is increasingly utilized also in pediatric oncology due to its ability to combine functional and anatomic information, thereby enhancing diagnostic accuracy and improving patient management. However, [18F]-FDG uptake in children differs physiologically from adults, and this radiotracer is not tumor-specific, with uptake occurring in various benign conditions such as inflammation, infection, and trauma. Accurate interpretation of pediatric [18F]-FDG PET/CT requires comprehensive knowledge of the normal distribution of FDG in children, recognition of physiological variants, and awareness of common benign lesions and PET/CT-related artifacts. Misinterpretation can lead to unnecessary follow-up studies, suboptimal treatment decisions, and/or increased radiation exposure. This review discusses the typical patterns of physiologic [18F]-FDG uptake in children, common benign mimics of malignancy, and potential artifacts and pitfalls encountered in pediatric [18F]-FDG PET/CT imaging, focus especially on head and neck (lymph nodes), brown adipose tissue, bone marrow and thymus. By increasing familiarity with these patterns, this review aims to improve diagnostic confidence, reduce interpretive errors, and promote safer and more effective imaging practices in pediatric oncology.