Optimisation of an image plate system with respect to tube voltage An observer performance study based on chest and pelvis images

In this study we evaluate the clinical image quality of a computed radiography system for different tube voltages. Images of anthropomorphic phantoms were produced and the quality of the images was evaluated using visual grading analysis (VGA) by a group of experienced radiologists. Two different X-ray examinations were investigated: chest PA and pelvis AP. The exposure conditions were set so that the effective dose for each technique was approximately the same in all exposures regardless of the tube voltage. The aim of the study was to investigate if any kV setting was assessed as preferable. Our results show that the image quality is improved when lowering the kV settings in both pelvis and chest radiography with the Fuji computed radiography system used. The improvement is marginal in chest radiography but more pronounced for pelvis investigations. The study also illustrates the differences in effective dose obtained using different methods for calculation.