Utility of PET-MRI in Surveillance of Paediatric Brain Tumours

This study is looking at whether a combined PET-MRI scan (which measures both structure and metabolic activity in the brain) is better than standard MRI alone at detecting whether brain tumors have come back in children after treatment. **You may be eligible if:** - You are a child with a diagnosed or suspected malignant brain tumor - Doctors are uncertain whether your tumor has returned based on regular MRI scans - You are expected to live at least 3 more months - You can complete an MRI scan without general anesthesia **You may NOT be eligible if:** - You cannot tolerate an MRI without general anesthesia - You have diabetes or other conditions that cause high blood sugar - You are pregnant - You are too large to fit in the scanner - You have a pacemaker, non-compatible metal implants, or reduced kidney function that makes MRI unsafe Talk to your doctor to see if this trial is right for you.