Effect of KVp in Digital Image Quality

Abstract

This research aimed to evaluate the effect of KVp in digital image quality ,this study was conducted it the modern medical center , before the date collection peocess has calibrated x_ray devices . The Tube voltage (KVp) reduction results in a parallel increase in film contrast that can improve image quality. 8 phantom images were scanned with the tube voltage varied between 43 and 120 KVp, and the mAs adjusted to maintain a constant exposure level between 1.25 and 160 mAs. At a constant x-ray tube voltage, the surface dose and energy imparted were directly proportional to the input exposure, the result indicating that decreasing the kilovoltage will improve image quality by improving the contrast, the image contrast substantially increased with low tube voltage. However, with identical dose, use of 60 kV and 40 mAs resulted in higher contrast compared with Contrast at 105 kV and 2.5 mAs. The main finding of the study was there is no relation between kvp increasing and contrast , Dmax , Dmin . This finding is due to possibility of monpulatit density and contrast in digital image , and it's not like film screen system where the density and contrast were control mainly by kvp .this image quality also was evaluated by visual perception by questionnaire 50 professional radiologist were asked to evaluate the image quality , the result showed that 34% of from the asked group evaluated the image in the range of better resolution , 28% of from the asked group evaluated the image in the range of acceptable resolution , 38% of from the asked group evaluated the image in the range of poor resolution , were 34% of from the asked group evaluated the image in the range of better resolution , were 62% from asked group evaluated the image in the range of better contrast ,24% of from the asked group evaluated the image in the range of acceptable contrast , 14% from the asked group evaluated the image in the range of poor contrast ,the final result were find that no fixed relationship between increasing KVp and contrast