ABSTRACT
The major activity of diagnostic radiologists is commonly called fIlm reading. It consists of looking at the x-ray images of people which are generally recorded on films, determining if any abnormal structures or configurations are present in the images, and then making inferences about the conditions or diseases that might cause the abnormal appearances. Like most human endeavors, film reading is subject to error and for the diagnosis of some types of diseases they are surprisingly high. Thirty percent false negatives and 5% false positives are typically found when the diagnosis of tuberculosis (Garland, 1959) or of small lung cancers (Guiss & Kuenstler, 1960) on survey chest films has been studied.
