Contrast-detail evaluation of a full-field digital mammography system

We have been investigating the potential of large-area flat-panel a-Si:H imaging devices for full-field digital mammography. The performance of a clinical mammographic system specially developed to provide geometric direct magnification equipped with an a-Si:H digital detector in conjunction with a series of Gd2O2S:Tb phosphor screens was evaluated in terms of image quality and entrance surface dose by using the contrast-detail CDMAM phantom over a range of exposure levels. We also compared the contrast-detail detectability properties of the a-Si:H-based digital imaging system with those of a conventional screen-film combination. The results from this study reveal the superiority of this prototype a-Si:H-based digital imaging system both in terms of contrast-detail resolution and significant entrance surface dose reduction in comparison with the conventional screen-film combination. These advantages are of particular significance in the breast imaging. Therefore, the combination of a-Si:H digital array with the direct magnification mammography system has the potential to fulfil the image quality requirements for full-field digital mammogarphy and to offer significant improvements in the efficient early detection of breast cancer.