Radiograph quality evaluation for exposure variables--a review.

Good quality radiographs are essential for making accurate diagnoses. Many factors influence the quality of radiographs including the x-ray machine specifications and settings, the darkroom environment and processing, and the choice of ancillary x-ray equipment (cassette properties, film/screen selection, use and properties of a grid). In compiling a technique chart, many of these variables are standardized so as to provide dependable guidelines for selecting the appropriate exposure settings (mAs and kVp) for a radiographic study. The systematic evaluation of image blackening, peripheral blackening, and the visibility of the gross image detail and contrast will facilitate the development of a technique chart as well as determining the source of the problem and necessary exposure setting changes for radiographs that are suboptimal. A flow diagram is described that will assist with the systematic evaluation of radiographic quality and provide guidelines for correcting exposure errors.