Clinical utility of [¹⁸F]-FET PET Imaging in pediatric brain tumors: a case series

Primary brain tumors are the most common solid neoplasms in children and young adults. Surgical resection remains the cornerstone of treatment, with extent of resection and histopathology serving as main prognostic factors. While magnetic resonance imaging (MRI) is the gold standard for neuroimaging and surgical planning, [¹⁸F]-fluoroethyl-L-tyrosine positron emission tomography ([¹⁸F]-FET PET) may provide complementary metabolic insights. We evaluated the role of [¹⁸F]-FET PET combined with preoperative MRI in the management of pediatric brain tumors.

We retrospectively selected from a single-institutional registry 12 patients aged 16 years or younger who underwent surgical treatment for brain tumors at a single tertiary pediatric center between 2013 and 2024. All patients underwent preoperative [^18F]-FET PET in addition to MRI. PET findings were used to support biopsy targeting, surgical resection planning, and follow-up assessment. Histopathological and molecular diagnoses were reviewed according to the 2021 World Health Organization (WHO) classification of central nervous system.

Histopathological diagnoses included low-grade gliomas and glioneuronal tumors, high-grade gliomas, diffuse midline glioma, and embryonal tumors. [^18F]-FET PET identified metabolically active neoplastic tissue in 11 of 12 patients. One false-positive finding occurred in a previously treated lesion and was ultimately attributed to reactive gliosis. PET/MRI integration supported surgical decision-making in all cases and proved particularly useful in differentiating tumor recurrence or progression from treatment-related changes during follow-up.

In this single-institution pediatric series, [¹⁸F]-FET PET had high utility in preoperative assessment of pediatric brain tumors. Its integration with MRI provided valuable additional data to guide surgical targeting, especially when conventional imaging was inconclusive. These findings support the use of [¹⁸F]-FET PET in precision pediatric neuro-oncology, but considering the limited number of patients enrolled in this study, larger prospective studies are needed to define its role in pediatric neuro-oncology.