Sensitivity Characteristics Of A Prototype Selenium Plate Detection System For Digital Radiographic Imaging

Abstract

We present an X ray measurement methodology with some preliminary X ray sensitivity characteristics for a prototype digital radiography system using amorphous selenium as the primary image receptor. As an imaging modality this experimental electrostatic system has the potential to replace film in existing general diagnostic radiography procedures. The imaging plate consists of a 360 micron layer of amorphous selenium deposited on an aluminumoxide substrate. An initial plate charge of 1400 volts (3.9 volts per micron) was exposed to X ray spectra produced with 50, 70, and 90 kVp with total filtration of 3 mm aluminum and 9 cm lucite. After this exposure the plate was scanned by a bank of electrometer probes at a distance of 100 microns. Sensitometric comparisons were then made to a conventional calcium-tungstate film-screen combination. The sensiometric response of the system is shown to be linear with an almost four fold increase in exposure latitude.