Safety Study of the Repeated Opening of the Blood-brain Barrier With the SonoCloud® Device to Treat Malignant Brain Tumors in Pediatric Patients

This study tests whether a device called SonoCloud — which uses ultrasound to temporarily open the blood-brain barrier (a protective layer around the brain) — can help chemotherapy drugs reach brain tumors more effectively in children and teenagers. **You may be eligible if...** - Your child is between 5 and 17 years old - Your child has a malignant brain tumor above the brainstem (e.g., malignant glioma, ATRT, ependymoma) - The tumor has come back or grown after at least one prior treatment - Your child is scheduled to receive carboplatin chemotherapy - Your child can undergo MRI scans without sedation - Your child's performance level is above 50% on the standard medical scale **You may NOT be eligible if...** - Your child is under 5 or 18 or older - Your child cannot tolerate MRI without sedation - There is a risk of brain herniation (life-threatening brain swelling) - Your child is not receiving carboplatin Talk to your doctor to see if this trial is right for you.