Tomoko Kusama

Oita University of Nursing and Health Sciences

　　Diagnostic X-rays are the largest artificial source of radiation exposure to the general public in the world. In Japan, the per capita dose of medical exposure has formerly been very similar to that of natural radiation exposure, 2.4 mSv per year. Recently, the frequency of diagnostic X-rays per 1000 population and the attributable risk of cancer from X-ray diagnosis in 15 developed countries were reported. These values in Japan were 1,477 and 3.2％, respectively. Both values were the highest in the 15 countries. Frequencies of upper GI tract examinations and CT scans, which give high effective doses to each patient, were particularly higher in Japan than in those other countries. Justification and optimization of radiation protection are essential for the control and management of medical exposure. In Japan, all medical doctors are able to carry out radiation diagnoses. Therefore it is necessary for general practitioners to be concerned about medical exposure and to have skill in the protection of patients from radiation.

Keywords：Medical exposure, Attributable risk, Justification of examination