Projection Radiography

Indirect flat panel x-ray detectors (scintillator based)scintillatorTFT sensorAn indirect flat panel detector uses a scintillator to convert x-rays to light,and then the light signal exposes the TFT and produces the electronicsignal. One of the limitations of this geometry is that unlike a screen filmcassette, the light has to propagate to the TFT detector across thethickness of the scintillator – since most of the interactions occur at theentrant surface. To help preserve spatial resolution, most high-end indirectflat panel detectors incorporate a CsI phosphor, where the needle likestructure of CsI crystals helps to channel light to the TFT with less blurring.34