We have been investigating the potential of large-area flat-panel a-Si:H im
aging devices for full-field digital mammography. The performance of a clin
ical mammographic system specially developed to provide geometric direct ma
gnification equipped with an a-Si:H digital detector in conjunction with a
series of Gd2O2S:Tb phosphor screens was evaluated in terms of image qualit
y and entrance surface dose by using the contrast-detail CDMAM phantom over
a range of exposure levels. We also compared the contrast-detail detectabi
lity properties of the a-Si:H-based digital imaging system with those of a
conventional screen-film combination. The results from this study reveal th
e 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. Thes
e advantages are of particular significance in the breast imaging. Therefor
e, the combination of a-Si:H digital array with the direct magnification ma
mmography system has the potential to fulfil the image quality requirements
for full-field digital mammogarphy and to offer significant improvements i
n the efficient early detection of breast cancer.