Digital X-Ray

Digital X-ray machines commonly use direct or indirect-conversion-based FPDs (Flat Panel Detectors) to detect X rays. A direct-conversion-based FPD, which converts received X rays into electric signals directly, is made up of an amorphous selenium layer and a TFT array. While an indirect-conversion-based FPD is built with an amorphous silicon layer, a photodiode array and a TFT array are used to convert X rays into visible light first with an amorphous silicon layer, and then convert into electric signals with a photodiode array.

A processor is used to control bias voltage imposed on TFT array, and also transmit the charge stored in TFT to a signal acquisition circuit according to a specific sequence by multiplexing. The signal acquisition circuit has an analog front end to convert the charge into voltage and amplify the voltage which represents power level of X-ray. The amplified signal is converted to digital signal by an A/D converter, and then processed by a DSP to create images. These images could be displayed on screen, printed or transmitted to a remote terminal for medical diagnosis.

With the introduction of new materials to FPDs and the development of digital image processing technology, digital X-ray machines with higher resolution and faster and more accurate image reconstruction are set to replace traditional X-ray devices.

Less