The number of CT examinations is dramatically increasing due to recent technical advances including multi-slice spiral CT. Although the benefits of CT outweigh the risks of radiation exposure of CT, radiologists should alert to the potential harmful effects of CT and avoid unnecessarily high CT dose, especially for pediatric CT examinations. To accomplish this, we should understand CT radiation dose and be familiar with imaging techniques of reducing CT dose without degrading diagnostic image quality. In addition, it is important to spread this balanced and useful information into CT referring clinicians, radiologists in training, and medical students.