Method Research And Implementation Of Determination Of The Detective Quantum Efficiency Of The Digital X-ray Imaging Devices

Digital X-ray imaging devices are increasingly used in medical diagnosis and will widely replace conventional (analogue) imaging devices such as screen-film systems or analogue X-ray image intensifier television systems in the future. Compared with the traditional devices, the digital device has many advantages, best of all them decrease the dose of X-ray, but improve the imaging quality, furthermore them could carry out the imaging disposal according to the demand of the doctors. It is necessary, therefore, to define parameters that describe the specific imaging properties of these digital X-ray imaging devices and to standardize the measurement procedures employed. There is growing consensus in the scientific world that the detective quantum efficiency (DQE) is the most suitable parameter for describing the imaging performance of an X-ray imaging device. The DQE describes the ability of the imaging of the imaging deviece to preserve the signal-to-noise ratio from the radiation field to the resulting digital image data. Since in X-ray imaging, the noise in the radiation field is intimately coupled to the air kerma level, DQE values can also be considered to describe the dose efficiency of a given digital X-ray imaging device. The DQE is already widely used by manufacturers to describe the performance of their digital X-ray imaging device. The specification of the DQE is also required by regulatory agencies (such as the Food and Drug Administration (FDA)) for admission procedures.This project's objective is to research the method of determination of the detective quantum efficiency of the digital X-ray imaging devices and develop a test soft. The project analyzes the test results, by many practices.This project determined DQE by the methods in accordance with IEC standards, for example, IEC62220-1:2003 and IEC62220-1-2:2007. This project determined the DQE of two typical detectors, DR100 type of amorphous silicon flat plate detector and MDR100 type of amorphous selenium detector. The mearsured typical DQE values (at Olp/mm) are 0.34 and 0.55 respectively. The calculation results are compared with an authoritative test report, and the measured values are 3.6% lower than the test report's. The conclusion is that the procedure and the software of determination of DQE can be accurate for data acquisition, processing and calculation.