RESUMO
Objective To explore the exposure condition of DDR, screen -film radiography and the radiation dose to patients, and evaluate value of the DDR system. Methods Five thousand images of DDR and screen-film radiography were selected and then analyzed by three junior radiologists and two senior radiologists. Results 1.The quality of the images was classified into grades A ,B ,C: grade A in 92.8 % , grade B in 7.2 % , grade C in 0% ,waste in 0 % for DDR group and grade A in 40.8% , grade B in 41.7 %,grade C in 15.5 % ,waste in 2% for screen-film radiography group. 2. The required voltage of DDR system raises 3-24kV than screen-film radiography and radiation exposure was increased about 25 % . Conclusions The imaging quality of DDR was obviously higher than the screen -film radiography, but the disadvantage of DDR system was the higher exposure condition required, which increase X-ray radiation dose for patients.