Positron emission tomography imaging of inflammation and infection in children: an update

Positron emission tomography (PET) has been used in pediatric oncology since the modality gained traction 20 years ago but has been used more sparingly in infectious and inflammatory diseases due to the ionizing radiation involved. However, more recent PET/CT systems allowing for the reduction of radiation dose have resulted in markedly more referrals, for these indications, over the past decade. Pediatric patients present unique challenges due to age-dependent physiology, nonspecific symptoms, and comorbidities, complicating diagnosis and limiting the utility of conventional imaging. [¹⁸F]-Fluorodeoxyglucose ([¹⁸F]FDG) PET/CT offers sensitive whole-body assessment, allowing the evaluation of systemic disease burden, guiding targeted microbiological sampling, and frequently contributing to differential diagnosis. Diagnostic accuracy is generally high for detecting active disease, and PET findings frequently lead to treatment modifications. Optimized imaging protocols that reduce radiation exposure, shorten acquisition times, and often eliminate the need for sedation have become even more important with the introduction of high sensitivity long axial field-of-view (LAFOV) PET/CT systems. LAFOV PET/CT also enables use of pathogen- and immune-targeted radiotracers with long half-lives in humans and may therefore combined with artificial intelligence-driven reconstruction techniques significantly enhance specificity, image quality, and feasibility of repeated PET imaging in children. In this review, we synthesize current evidence, clinical indications, technical considerations, and emerging technologies to provide a practical framework for integration of PET into pediatric diagnostic pathways for infection and inflammation.