Pre-radiation temozolomide.

Better treatments are needed for high-grade gliomas (HGG), and new ways of treating this disease should be tested. The investigators want to see if giving medicine before radiation works well. After radiation, MRI scans can be harder to understand because radiation changes how the brain looks on the scan. If new medicines are given before radiation, the scans are easier to read. First, the investigators need to find out if giving chemotherapy early works using a drug we already know can treat gliomas. The investigators will start with temozolomide, which is the only chemotherapy approved by the FDA for HGG. If this approach is successful, the investigators can then test new drugs using this screening method.