Hard copy versus soft copy display of 2,000 digital chest images

Using receiver operator characteristic (ROC) analysis, the authors have compared observer performance of analog film, 2K cathode-ray (CR) film, and 2K CR interactive soft copy for the detection of simulated nodules projected on an anthropomorphic chest phantom. Optimum technique for the CR system was determined by subjective evaluations of image quality by experienced radiologists over a range of radiographic techniques. For each display condition there were 46 images, consisting of images of solitary nodule in an area of high surrounding contrast (n = 18), a nodule in an area of low surrounding contrast (n = 19), or no nodule (n = 9). For each display condition, four observers determined the presence or absence of a nodule using a six-point confidence scale