This study will apply a novel imaging technique in patients with brain tumors to systematically evaluate the impact of various imaging parameters on image appearance, contrast, signal, and tumor sharpness, and to optimize the technique to maximize tumor visibility while minimizing scan time and image artifacts.

This study is for patients with recurrent/progressive medulloblastoma, which is a type of childhood brain tumor. Participants in this study will receive intravenous (IV, into the veins) bevacizumab and intrathecal (into the spinal fluid) or intraventricular (into the fluid surrounding the brain) etoposide and cytarabine in combination with five oral (taken by mouth) chemotherapy drugs as a possible treatment for recurrent/progressive medulloblastoma. Total study duration is about 1 year and depending on how well a participant tolerates the medications and the response of the disease, the patient may continue the treatment after the first year.

Glioblastoma adaptive, global, innovative learning environment or GBM AGILE trial is to identify effective therapies and improve survival for a type of brian cancer called glioblastoma (GBM) and to match effective therapies with adult patients with newly diagnosed or recurring glioblastoma. Eligible participants will have a 50/50 chance of taking either standard therapy medications or a medication not yet approved by the FDA called regorafenib during their standard of care treatment for GBM.