The flat-panel detectors (FPDs) are replacing conventional diagnostic x-ray imaging detectors. The indirect FPD consist of a scintillator and an amorphous silicon TFT-array has many advantages over other detectors such as direct FPD and CR (computed radiography). Amongst of all, the indirect FPD having more than twice DQE (detective quantum efficiency) can obtain equivalent image quality with much less dose than other detectors.