There are two main performance indicators for evaluating the quality of flat panel detectors: Detective Q uantum E fficiency (DQE) and spatial resolution. DQ E determines the resolution of flat panel detectors for differences in tissue density; spatial resolution determines the resolution of tissue microstructure. Investigating DQ E and spatial resolution can evaluate the imaging capabilities of flat panel detectors.
Second, the way in which the visible light generated by the scintillator is converted into an electrical signal also affects DQ E . In a flat panel detector of yttrium iodide (or yttrium oxysulfide) + thin film transistor (T FT), since the array of TF T can be made as large as the area of the scintillator coating, the visible light does not need to pass through the lens. Refraction can be projected onto TF T with no photon loss in between, so DQE is also high; in flat panel detectors of cesium iodide (CsI) + CCD (or CM OS), due to C CD (or CM) The area of OS) cannot be as large as the scintillator coating, so it needs to be refracted and reflected by the optical system to project all the images onto C CD (or CM OS). This process causes loss of photons, so DQE Relatively low.