DQE of digital x-ray imaging systems: a challenge for standarization

In July of 2000, a new Working Group (WG33) in IEC/SC62B met for the first time to develop a new IEC standard for the measurement of the detective quantum efficiency (DQE) of digital x-ray imaging detectors. Experts from meanwhile nine countries are involved. Because of the manifold systems on the market intended for different applications, it was decided to limit the scope of the standard to static systems to be used in general radiography. Dynamic systems (fluoroscopy), systems for mammography and dental systems are excluded but may be treated in additional standards later on. For the measurement of the spatial frequency dependent DQE, two methods are planned: the edge method and the grating method. Four beam qualities out of the IEC RQA series and three dose levels will be defined. The measurement of modulation transfer function (MTF), noise power spectrum (NPS), and characteristic curve will be specified. The evaluation of DQE will be either via the classic method, using the MTF, or via a new method relating on the calculated input modulation. Furthermore, the form to present the results will be specified.