Radiologic examination that requires radiation exposure for the purpose of diagnosis of the disease in the medical field have been implemented. In this regard, the IAEA (International Atomic Energy Agency, under), the International Commission on Radiological Protection (ICRP) and other radiation control related agencies/professional organizations recommend to comply the justification and optimization for the purpose of medical radiation exposure control. However, activity to enhance the optimization over the last two decades are numerous, relatively less justification activity is not recognized as a problem. The principle of justification should be considered first, before the optimization principle, is an important step to determine whether or not unnecessary radiation. In the field of radiology, individual countries around the world have developed and are utilizing evidence-based clinical guidelines in order to augment clinical decision-making by physicians when requesting or prescribing a radiologic examination. This research is also one of these activity and will ultimately reduce unncessary radiation exposure to the patient, and to develop a Korean 'evidence-based clinical guidelines for imaging' to ensure proper enforcement of medical imaging tests.