The Research Of Image Quality And Exposure Level Of Digital X-ray Imaging Techniques

Objective To research the relationship betweent image quality and exposure dose of digital radiograpy, the exposure dose levels for different digital radiography techniques were compared. The optimized exposure parameters for digital radiography were determined. To assess and quantify the influence of monitor configures of image acquisition workstation in digital radiography on image quality and exposure dose. The methods to raduce the patient dose and improve the image quality were explored.Material and method The imaging quality of CR and conventional screen-film combination was evaluated by mearsuring the noise level of images. By analysing the exposure dose and image noise level, the proper exposure dose levels for CR were recommended. The image quality of CR and DR, the relation between image displayer configuratons and imaging exposure levels of digital radography system were researched with the detectablity for phantom contrast and detail. A ROC analysis was performed with TRG phantom at different exposure settings for two different DR. A contrast-detail phantom CDRAD2.0 was exposed with varioust dose levels and the IQF of phantom images were calculated and it was used to optiming exposure parameters for pelvic examination. A low contrast phantom was made to evaluate the detectibality of blood vessel at defferent kVp, mAs settings for digital substruction angiograpy. Depended on the image quality at different exposure dose, intensity of scatter at operating position and ESDs, the general optimized exposure settings were determined.Result The WS is significant different for various screen-film system at lower spatial frequency, but at higher spatial frequency, the differents has no satatistic meaning. For CR, as the exposure dose increase, the noise level drops sharply. Compare to the screen-film system, in order to get the same WS level, the exposure dose for CR will need 1.4 times of that of screen-film. The DR system shown better low contrast detectibality comparaing to CR. DR...