In 1995, we have published a paper about the basic data on the relation between X-ray exposure equipment and patient dose in Vol. 17 of the Journal "Environment Research and Control". In this time, we questioned hospitals in Okayama Prefecture about exposure equipments of abdomen. And we compared each hospital's exposure equipments with the basic data, calculated each patient dose, then we studied that differences. Various imaging system, for example; screen/film or imaging plate has been used at each hospitals, so that exposure are various and patient doses are very different. The exposure equipment decide that the X-ray photograph is good or bad, so we cannot treat it easily. But we think that we have to try to take X-ray photographs which are suit the purpose of diagnosis which as a small patient dose as possible
