CHEST RADIOGRAPHIC IMAGE QUALITY - COMPARISON OF ASYMMETRIC SCREEN-FILM, DIGITAL STORAGE PHOSPHOR, AND DIGITAL SELENIUM DRUM SYSTEMS - PRELIMINARY-STUDY

Conventional screen-film radiography does not display all regions of t he thorax satisfactorily. Three chest radiographic techniques display both the lung and the mediastinum with good contrast. These techniques are asymmetric screen-film (ASF), digital storage phosphor (DSP), and digital selenium drum (DSD) imaging. ASF systems use two asymmetric s creen-film combinations to produce a wide-latitude image of the thorax with good contrast in the lungs. In DSP systems, image data are acqui red digitally with a wide dynamic range by using the optical output of a photostimulable phosphor plate; in DSD systems, the wide-range digi tal image data are acquired by using the electronic charge generated o n a drum coated with a thin layer of amorphous selenium, The appearanc e of a DSP or DSD radiograph is then determined by user-selected image processing operations: tone scaling, spatial frequency processing, an d dynamic range compensation. Digital chest radiographs processed with strong regional equalization provide both excellent contrast in the l ungs and effective display of the mediastinum and chest wall. At visua l comparison, the high lung contrast and good mediastinal, retrocardia c, and subdiaphragmatic detail provided by the DSD method distinguish it from the other two methods.