Purpose: We examined thorax-specific (XGS/SRES-G, HG-M/UR-1, IS200/IEF-RA) and general (XGS/SRES-G, HG-M/UR-2) screen-film systems to determine the optimal systems for thoracic radiography and invcstigated how they should be used. The systems are referred to hereafter as XG/C, HG/1, IS/IEF, XG/G, and HG/2, respectively. Method: Crossover light, characteristic curves, MTF and RMS were used for objective evaluation. For subjective evaluation, 50 staff were asked to view thoracic phantoms and their clinical images and asked to make a final comment about their quality. Results: 1)HG/1 and IS/IEF performed very well on subjective evaluation, obtaining excellent comments with respect to most of the features evaluated in this study. 2)XG/G performed poorly with respect to each of the features evaluated in this study, but was considered to provide good balance for thoracic use. 3)There was very little correlation between physical features of sharpness and visual evaluation. Conclusions: 1)HG/1 and IS/IEF were superior as imaging systems for thoracic radiology. 2)XG/G could be used effectively for both thoracic and general radiology provided tube voltages and additional filters are chosen appropriately. 3)Contrast seems to influence the correlation between physical end visual sharpness
