The working principle of dr

Different from the gradual digitization of CR, DR (Digital Radiography) is also called digital photography. Early DR used CCD (digital coupler) coupled with intensifying screen and optical lens to obtain digital X-ray images, which is somewhat similar to the working mode of image intensifier and CCD (see figure 1). This technology is considered as the first generation of disaster recovery technology.

At present, the widely used DR mainly uses flat panel detector (FPD) to scan and directly read the image signals generated by X-rays. The imaging principle is that X-ray signals are first converted into visible light, which is gathered by a algae film layer (TFT) composed of photodiodes, directly read by a special reading circuit, and sent to a computer system for processing. The working principle is shown in Figure 2. At present, flat-panel probes are divided into indirect conversion digital photography (IDDR) represented by amorphous silicon (a:Si+CsI) and direct conversion digital photography (DDR) represented by amorphous selenium (a:Se). The working principle of a:Si+CsI indirect conversion digital photosensitive plate is shown in Figure 3.

The composition of DR generally includes high voltage generation port, X-ray tube and bracket, flat panel detection port and system control port. Compared with the traditional X-ray signal, the DR system uses flat-panel detection X-ray receiver to replace the traditional intensifying screen and film, which realizes the digitization of X-ray signal, has high dynamic range, high spatial resolution and density resolution, further reduces the exposure agent and is more expensive.