Patent ID: 6037112
Filing Date: 2000-03-14
Classification: G03C,Y10S

Abstract:
A radiographic film for recording medical diagnostic images of soft tissue through (a) exposure by a single intensifying screen located to receive an image bearing source of X-radiation and (b) processing, including development, fixing and drying, in 90 seconds or less comprised ofa film support transparent to radiation emitted by the intensifying screen and having opposed front and back major faces andan image-forming portion for providing, when imagewise exposed by the intensifying screen and processed, an average contrast in the range of from 2.5 to 4.0, measured over a density above fog of from 0.25 to 2.0,wherein the image-forming portion is comprised ofa processing solution permeable front layer unit coated on the front major face of the support capable of absorbing up to 70 percent of the exposing radiation and containing (a) hydrophilic colloid, the hydrophilic colloid being limited to less than 40 mg/dm.sup.2, and (b) radiation-sensitive silver halide grains having an average thickness of greater than 0.3 .mu.m and an average aspect ratio of less than 5, the coating coverage of the silver halide grains being limited to less than 40 mg/dm.sup.2, based on the weight of silver, anda processing solution permeable back layer unit coated on the back major face of the support containing (a) hydrophilic colloid, the hydrophilic colloid being limited to less than 40 mg/dm.sup.2, (b) silver in the form of radiation-sensitive silver halide grains accounting for from 20 to 45 percent of the total radiation-sensitive silver halide present in the film, tabular grains having a thickness of less than 0.3 .mu.m and an average aspect ratio of greater than 5 accounting for at least 70 percent of the total projected area of the radiation-sensitive silver halide grains in the back layer unit, and (c) a dye capable of providing an optical density of at least 0.40 in the wavelength region of the exposing radiation intended to be recorded and an optical density of less than 0.1 in the visible spectrum at the conclusion of film processing, the dye being excluded from a first layer of the back layer unit containing at least 20 percent of the radiation-sensitive grains within the back layer unit and being present in at least one remaining layer coated farther from the support than the first layer,the hydrophilic colloid of the front layer unit being hardened to a lesser extent than the hydrophilic colloid of the back layer unit andthe back layer unit having a speed ranging from 0.3 log E to 1.0 log E slower than the front layer unit, where the speed of the front layer unit is measured at a density of the front layer unit of 1.0 above fog and the speed of the back layer unit is measured at a density of the back layer unit of 1.0 above fog.