title: Metal screen-film detector MTF at megavoltage x-ray energies.
abstract: The MTF of metal screen film detectors used in radiation treatment verification has been measured at 4 and 8 MV x-ray energies. The results show that lead screens provide better resolution than copper screens, and a single-emulsion film offers considerable advantage over the traditional double-emulsion film. A rear lead screen was found to seriously degrade the resolution properties of a front lead screen single-emulsion film detector. The detector MTF was found to be energy dependent. In general, both the low and the high spatial frequency response decreased with increasing x-ray energy. This, in part, accounts for the noticeable image quality difference between 4 and 8 MV radiographs.
mesh_terms: D008670:Metals; D011859:Radiography / Q000295:instrumentation*; D013679:Technology, Radiologic; D014965:X-Rays
chemical_list: D008670:Metals