Over the last 50 years, diagnostic imaging and image quality has grown from a state of infancy to a high level of maturity. Detective quantum efficiency (DQE) is one of the most important measures in the assessment of image quality and detector performance. This book has focus on computation of DQE of radiographic screen-films. In this book key parameters in DQE computation are well discussed, including modulation transfer function (MTF), Noise Power Spectra (NPS), gamma of film and photon fluence, which are discussed mostly in scattered and non-specific books. This work contains computation of some screen-films namely Lanex Regular/T-Mat G/RA and Lanex Regular/T-Mat L/RA using experimental data of our original work. At the end, there are some conclusions to evaluate two mentioned screen-films in terms of image quality and performance using computed detective quantum efficiency for each screen-film. Moreover, this book has good enough discussions for DQE computation and interesting topics in medical imaging area.