Radiology, Vol 165, 313-318, Copyright © 1987 by Radiological Society of North America
Mammographic dual-screen-dual-emulsion-film combination: visibility of simulated microcalcifications and effect on image contrast
C Kimme-Smith, LW Bassett, RH Gold, D Roe and J Orr
Department of Radiological Sciences, UCLA School of Medicine 90024.
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.
