External radiotherapy occupies a prominent place in cancer treatments. The constructions of the linear accelerators of electronics bunkers are costly and this factor is limiting so that more equipment is installed. It is necessary to research constructive options with the objective of reducing costs, without loss of the guarantee of structural stability and radiological protection as a barrier. In the screening study of these facilities, various materials may be employed for radiation attenuation. Reinforced concrete is used in many of these facilities, either for its cost or the constructive facility in Brazil, due to the knowledge of this material. The objective of this study was to design and analyze a bunker buried in reinforced concrete and as a comparative of costs the structure of an ungrounded bunker was also designed, also in reinforced concrete. Some advantages and disadvantages of each structural system were indicated, as well as the costs of the basic structure of two models. The structure of the walls, accesses, slabs, beams and pillars, as well as foundations, in terms of cost, has the ratio of 4 times the bunker not buried to the buried bunker, a significant value in the installation of a radiotherapy service.