Dexamethasone is an effective medication to ameliorate radiation induced headache and vomiting. In our Toronto experience dexamethasone in low doses (1 mg/m2/day) is sufficient in treating these symptoms. However this experience is not shared from many neuro-oncology centers of excellence that more commonly use 5 mg/m2/day according to the results of the trans-Canadian survey. A prospective multicenter trial evaluating the effectiveness of dexamethasone in different dose regimens in symptomatic children while undergoing CNS radiation will elucidate the appropriate dose.