THE USE OF A CONTRAST-DETAIL TEST OBJECT IN THE OPTIMIZATION OF OPTICAL-DENSITY IN MAMMOGRAPHY

In mammography, it is important that the maximum amount of diagnostic information is obtained from each radiograph. One of the factors influ encing image quality is the optical density of the film. In this study , a contrast-detail test object was used to establish the optimum opti cal density value on the basis of signal-to-noise ratio (SNR) for two mammographic film-screen combinations under particular processing cond itions. The optimum optical density, taken as being the point at which the threshold contrast is a minimum varied little with detail size. T he optimum optical density for the Fuji him-screen combination with Ph otosol chemistry was found to be higher than that for the Kodak film-s creen combination and Kodak processing conditions studied. Although th e actual values of optical density are specific to the fixed processin g conditions encountered, the technique has more general applicability .