<title>Signal-To-Noise Ratio, Dynamic Range And Contrast Sensitivity Of Radiographic Imaging Systems</title>

Abstract

Signal-to-noise ratio, dynamic and contrast sensitivity are three parameters used to describe performance or quality of electronic medical imaging systems or components. The meaning and significance of these parameters are discussed and their values for various systems, including conventional film-screen systems, are derived. An additional parameter, useful dynamic range, is introduced and related to existing systems. Under optimum conditions the signal-to-noise ratio of a radiographic imaging system will be determined only by quantum statistics. For a quantum limited system contrast sensitivity is related to x-ray dose and independent of the particular system used, analog or digital. The useful dynamic range of most electronic imaging systems is limited by system noise to a value less than that typically exhibited by conventional film-screen systems, 20:1 to 50:1.