Potential for unnecessary patient exposure from the use of storage phosphor imaging systems

Abstract

It is possible to use storage phosphor radiography (SR) devices in a manner that results in excess exposure to the patient without the operators knowledge. Because these SR systems have an automatic correction for the final optical density (OD) of the image, the technologist and radiologist will not be able to use excessive blackness of the image as a sign of overexposure. Tests reported here demonstrate that it is possible to obtain images of a chest phantom that appear acceptable with a 32 times difference in exposure (maximal exposure .86 R). It is possible to obtain exposures of a pelvis phantom that appear acceptable up to the tube limit of our machine (4.8 R). Tests of the Fuji AC-1 demonstrate that it will accept a much wider range of exposures than the AGFA ADC prototype which permits only a 7 times difference in exposure before the image is degraded.