External beam radiotherapy (EBRT) causes anxiety and claustrophobia in pediatric patients. To provide exact figures and radiation amounts, an appropriate sedation or anesthesia can be supplied. Alpha 2 agonist dexmedetomidine has been used for sedation and anesthesia in pediatric imaging. Dexmedetomidine has an advantage because it has minimal respiratory depression and no direct effects on myocardial function. We report repeated sedation with dexmedetomidine for 33 consecutive radiation therapies in 5 years old children.