What is the difference between the two flat panel detectors?
In a direct conversion flat panel detector
, the conversion of X-rays into electrical signals is completely dependent on the electron-hole pairs generated by the amorphous selenium layer. The level of DQ E depends on the ability of the amorphous selenium layer to generate charge. In general, the limit DQE of the indirect conversion flat panel detector of the structure C sI + T FT is higher than the limit DQ E of the a -Se direct conversion flat panel detector.
In the direct conversion flat panel detector, since no visible light is generated, no scattering occurs, and the spatial resolution depends on the size of the thin film transistor matrix per unit area. The larger the matrix, the larger the number of thin film transistors, the higher the spatial resolution, and the higher spatial resolution can be achieved with the improvement of the process.
In indirect-converted flat panel detectors, there is scattering due to the generation of visible light. The spatial resolution depends not only on the size of the thin film transistor matrix per unit area, but also on the control technique of the scattered light. In general, the spatial resolution of indirect conversion flat panel detectors is not as high as the spatial resolution of direct conversion flat panel detectors.