Mammographic dual-screen-dual-emulsion-film combination: visibility of simulated microcalcifications and effect on image contrast.

Three test objects simulating different mammographic problems were imaged with a new low-dose dual-screen-dual-emulsion-film combination and a standard screen film combination, with and without a moving grid, at 28 and 32 kVp, and with 0.3- and 0.5-mm focal spots. The new combination reduced exposure by 50%, but it failed to equal the other combination in the depiction of simulated microcalcifications, even when a different brand of film-processing chemicals was used. Compared with the standard screen-film combination exposed without a grid, the new combination exposed with a grid resulted in a superior image of dense parenchyma without an increase in dose. Furthermore, when the exposure time was decreased by 25% (rather than 50%), dense breasts were imaged with greater penetration by the new combination. A clinical trial of the new combination in 200 patients showed prominent quantum mottle and reduced contrast in regions of dense parenchyma. In addition, the skin and subcutaneous tissue were often poorly depicted with both standard and high-intensity illumination.