Integrated PET/MRI and Germline Variants to Differentiate Brain Tumopr Recurrence From Iatrogenicchanges in Children

60 children and/or adolescents (≤18 years) with a diagnosis of brain tumor (medulloblastoma, other embryonal tumors or high-grade gliomas), who have followed the contemporary adjuvant therapy protocol of post-surgical chemo and radiotherapy and completed radiotherapy for at least 6 months will undergo a brain MET-PET/MRI.