New Horizons in Molecular Imaging: FDG PET/CT and Quantitative Parameters in Pediatric Lymphomas

This review aims to comprehensively evaluate the current role of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in paediatric Hodgkin lymphoma (HL) and non-Hodgkin lymphomas (NHL) across diagnosis, staging, treatment response assessment, and prognostication. Emphasis is placed on quantitative metabolic parameters such as maximum standardized uptake values, metabolic tumor volume, total lesion glycolysis (TLG), quantitative PET index (qPET), and maximum tumor dissemination distance (D_max), highlighting their clinical applicability and subtype-specific prognostic implications. The contribution of PET/CT to initial staging in HL and FDG-avid NHL subtypes, as well as the prognostic value of interim and end-of-treatment scans, are detailed considering contemporary national and international guidelines. Furthermore, the prognostic relevance of metabolic PET parameters in pediatric NHL subtypes, including anaplastic large cell lymphoma, diffuse large B-cell lymphoma, and Burkitt lymphoma, is summarized. Emerging approaches such as radiomics, low-dose imaging strategies [PET/magnetic resonance (MR), AI-based CT-free PET], and novel CXCR4-targeted tracers like Pentixafor are also discussed. FDG PET/CT remains integral to clinical decisionmaking in pediatric lymphomas, guiding management from baseline evaluation through follow-up. Novel parameters such as TLG, qPET and D_max, together with dose-reduction strategies like PET/MR, may lay the foundation for future risk-adapted protocols and personalized treatment strategies.