This is a phase II study evaluating the feasibility of concurrent carboplatin given with focal radiation therapy in children age 12 months to < 21 years with newly diagnosed localized ependymoma who have no or minimal residual disease post-operatively (< 0.5 cm). The hypothesis is that utilizing carboplatin as a radiosensitizer is feasible and tolerable and may improve event-free survival (EFS) and minimize local recurrences as compared to historic controls. Following a neurosurgical resection and staging, patients who meet the eligibility criteria will receive standard fractionated radiation therapy at doses of 54 to 59.4 Gy to the primary site depending upon age. All patients will receive 35 mg/m²/day of carboplatin prior to each fraction of radiotherapy. Although significant neutropenia is not anticipated, G-CSF will be administered per study guidelines during radiation if neutropenia occurs. All patients will be followed for toxicity, response (resolution of residual disease) and event-free survival (EFS). Patients' tumor sample, blood and cerebro-spinal fluid (CSF) will also be prospectively evaluated to quantify the level of Survivin, a known inhibitor of apoptosis, via immunohistochemistry, Western Blot Analysis (in tumor tissue) and ELISA (in blood and CSF). The feasibility of obtaining these levels prospectively and in real time will be evaluated.