Medical imaging is an indispensible diagnostic tool in modern medicine enabling fast and accurate diagnosis. However, recent technological advances in medical equipment and increased utilization of the imaging modality have resulted in a significant increase in the exposure to ionizing radiation. The risk from radiation must be carefully considered in all examinations using ionizing radiation, especially in children. The risk of cancer in children from radiation exposure is higher than adults because pediatric patients are more radiosensitive and have more years ahead in which cancerous changes might occur. Therefore, pediatric protocols specifically designed for children must be used. However, many exams are still conducted using inappropriate adult protocols, which can result in excessive radiation. The most efficient way to reduce radiation is to avoid the examination if not justified. It has been suggested that one third to one half of pediatric CT exams are unnecessary or replaceable by other imaging modalities. If the exam is justified, then the parameters must be optimized to the imaging indication, scan area, body size, age, or weight of the patient according to the "as low as reasonably achievable" (ALARA) principle. The physician should always assess the radiation risk-benefit for each patient before ordering an examination using radiation.