Films, screens and cassettes for mammography.

Various film-screen combinations intended for mammography have been compared for image quality and for dose. Image quality was assessed as in an earlier paper, using a test object having details which are both realistic and quantitative. Relative doses required to give film densities of 1.0 were measured. The Kodak MinR-MinR combination was taken as a standard against which others were compared, and in general a lower dose was accompanied by poorer image quality. The Fuji NH film with Fuji Hi-Mammo screen was the sole exception, giving slightly better image quality at about half the dose required by the MinR combination. A number of cassettes were also compared with each other and with evacuated envelopes. The Dupont Cronex cassette and three carbon-fibre fronted cassettes all performed well in image quality.