title: Energy-selective filtration of dental x-ray beams.
abstract: Samarium is known for its ability to filter simultaneously low- and high-energy x-ray photons from an x-ray beam that are not useful in producing a diagnostic radiograph. This study was undertaken to determine the optimum thickness of samarium required to minimize patient exposure and exposure time. The results indicate that use of a filter thickness of 0.16 mm. minimized patient radiation exposure and permitted the use of an exposure time sufficiently short to minimize motion unsharpness. The incorporation of a 0.16 mm. samarium filter in the x-ray beam reduced exposure by about 40 percent as compared to a 2.5 mm. aluminum filter; the exposure time must be increased approximately twice to obtain optical densities equivalent to those produced with aluminum filtration.
mesh_terms: D005374:Filtration / Q000379:methods*; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D011861:Radiography, Dental; D012493:Samarium; D013997:Time Factors; D014962:X-Ray Film
chemical_list: D012493:Samarium