Digital X-ray and Ultrasound
Digital radiography involves radiological procedures, in which x-ray images are no longer recorded on analog x-ray films, but digitally. Instead of the film, the devices contain a scintillator that converts incident X-ray photons either into visible light or directly into electricity.
Older DR systems recorded the scintillation of the light-emitting layer optically reduced with a video camera, a CCD sensor or a CMOS chip. Today flat panel detectors, which are at least as large as the X-ray image, are used to increase the resolution of the area. They contain a layer of cesium iodide, a layer of microlens, and a layer of photodiodes.
Solid state detectors of rare earths, such as gadolinium oxysulfide or amorphous selenes, can convert the incident X-ray photons directly into electricity by passing them through the adjacent TFT layer without any visible light. The data collected in the detector are passed on digitally to a computer.