Abstract: An apparatus for determining the quality of X-ray tubes by analyzing filmed images of the focal spots produced by the tubes. In an exemplary embodiment of the apparatus, a slide scanner receives a filmed focal spot from an X-ray tube and scans it to produce a digital version of the focal spot. The digital focal spot is then analyzed by a personal computer to determine parameters relating to the focal spot such as its background and peak optical density, line spread function, modulation transfer function, skew, and loading. These parameters are then compared to parameter standards to determine whether the X-ray tube should be accepted or rejected under current quality standards.

Abstract: Described herein is a method of radiographic imaging providing low access time prior to the start of a user-requested X-ray exposure, while at the same time reducing or eliminating the imaging artifacts associated with short access times. The method includes the steps of exposing a radiographic detector for a time period t.sub.e ; reading the radiographic detector to obtain an exposure reading; reading the radiographic detector to obtain an offset reading, wherein the offset reading is obtained after a time period t.sub.w greater than t.sub.e ; and subtracting the offset reading from the exposure reading. Where the detector is subjected to readings lasting for periods t.sub.r prior to taking the exposure reading, detector readings lasting for t.sub.r are also taken during t.sub.w. After the final t.sub.r reading is taken during t.sub.w, the offset reading is then preferably taken after a period equal to t.sub.e.