Despite the rareness of radiation accidents, their potential consequences can be very serious, and appropriate medical management requires sufficient preparatory planning. To identify necessary factors for sufficient preparatory planning, three different radiation accidents were analyzed, i.e. the accidents in Goiânia, Brazil, 1987; Lilo, Georgia, 1997; and Tokai-mura, Japan, 1999. These radiation accidents have been chosen specifically because they provide a wide spectrum of potential radiation accident scenarios. After a brief description of the accidents and the following medical management, the measures taken are analyzed in terms of diagnosing radiation-induced health damage, determining the cause, dealing with contamination/incorporation, pathophysiological and therapeutic principles, preparatory planning, national and international cooperation and training. Several important factors are identified that should be considered in preparatory planning, i.e. preventing delayed diagnosis and training of medical personnel. Due to limited national resources, an intensified international cooperation to manage medical radiation accidents is of great importance.