Conventional building materials as protective barriers in dental roentgenographic installations

Abstract

An x-ray unit operating at 70 to 125 kvp, with 0.5 mm aluminum filtration, was used for transmission measurements on various commercial wall structural materials; cinder block with Portland cement or barium montar and tile facings, gypsum Pyrobar, gypsum plaster on metal lathes, and prefabricated steel. Each wall section was roentgenographed to determine the locations of minimum and maximum shielding. The locations were marked on the wall sections, and transmission measurements were taken at these points. Lead-attenuation data were also obtained, and wall transmission data were converted to lead equivalents, using the lead-attenuation data, and to concrete equivalents. A dental roentgenographic room with some typical barrier protection problems is illustrated and the maximum shielding that would be required in such an installation is discussed. Shielding requirements are shown for several work loads ranging from that encountered in a typical dental office to that of a busy dental roentgenographic installation. Attenuation measurements on the samples made under conditions of narrow-beam geometry indicated that the effective atomic number of all the materials except the barium mortar was sufficiently close to that of concrete to permit the use of the concrete broad-beam mass-absorption coefficient for computing changes in attenuation due to slight changesmore » in the thickness of any one of the component pants of a wall. The results on typical wall sections indicate that conventional walls provide significant and often adequate shielding in the dental voltage range. (TCO)« less