Flat panel detector for digital radiology using active matrix readout of amorphous selenium

Our goal is to develop a large area, flat panel, solid-state detector for both digital radiography and fluoroscopy. The proposed detector employs a photoconductive layer of amorphous selenium (a-Se) to convert x rays into charge. The charge image formed on the a-Se is electronically read out in situ using a two dimensional array of thin film transistors (TFTs), or 'active matrix.' Since the active matrix readout is capable of producing x-ray images in real- time, it can potentially be applied in both radiography and fluoroscopy. Investigation of the practical feasibility of this concept with a prototype x-ray imaging detector is described. Measurement of x-ray imaging properties, e.g. modulation transfer function (MTF) and x-ray sensitivity of the prototype are investigated, and the results compared with our earlier theoretical analysis.