This study is testing the Optune device for children with certain brain tumors, like high-grade glioma, ependymoma, and DIPG. The Optune device is a cap that emits electric fields to help stop cancer cells from growing. The study is split into two parts:

Stratum 1: For children with recurrent brain tumors, they will wear the Optune device alone. Researchers want to see if kids can use it daily and check for any side effects.

Stratum 2: For children with newly diagnosed DIPG, the Optune device will be used with radiation therapy. The goal is to see how safe and effective this combination is.

• Participants will need to wear the Optune device for at least 18 hours a day.
• The study could last up to 5 years, depending on how well the treatment works.
• There will be regular check-ups to monitor the treatment's effects.

Children must have specific types of brain tumors to join, and they need to be stable enough to handle the treatment. The study is open to boys and girls of all races and ethnicities. If you consider joining, talk to your doctor for more details.