Head injuries occur commonly in children and adolescents. Approximately 50% of children who visit hospital emergency departments with a head injury are given a CT scan, a considerable number of which are unnecessary. Unnecessary exposure to x-rays poses considerable danger to children, including increasing the lifetime risk of cancer because a child’s brain tissue is more sensitive to ionizing radiation. They also impose undue costs to the health care system. Clinical observation prior to CT decision making for children with minor head injuries is an effective approach.