RTBC Fundamentals Of Digital Radiography Practice Test

The readout of a DEL array is controlled by the thin-film transistor (TFT) backplane. In an active-matrix detector, each detector element has a TFT that acts as a switch. When a row is selected, the TFTs for that row turn on, connecting the charge stored on each pixel’s storage capacitor to the readout line so the signal can be read by the processing electronics. The stored charge on the capacitor represents the x-ray signal from that pixel, but the actual control of which pixel is read and when is governed by the TFT network. The other components—capture area (where x-rays are absorbed), scintillation layer (in indirect conversion, converts x-rays to light), and storage capacitor (holds the pixel charge)—play roles in signal generation and storage, not in controlling the readout sequence.