Soft Copy Digital Mammography

Soft Copy Digital Mammography creen-film mammography (SFM) has been the standard method used for breast cancer screening and making a clinical diagnosis. It is a valuable modality for the detection and differentiation of breast calcifications. The advantages are the high spatital resolution, the convinient display, and inexpensiveness. However, it has some inherent limitations such as its low detective quantum efficiency and the difficulty of post-processing after obtaining an image. Digital mammography (DM) has the potential to overcome the inherent limitations of SFM. DM systems directly qualify x-ray photons and decouple the process of x-ray photon detection from the image display. The digital images can be processed by a computer and displayed in multiple formats. Thus, DM is better than SFM for the detection of mass lesions due to its high contrast resolution. However, one of the main clinical tasks of digital mammography is the detection and characterization of breast calcifications. When comparing SFM to DM, SFM has an advantage over DM because it has higher spatial resolution then DM and the detailed image features may be more obvious. On the other hand, DM has higher contrast resolution with the ability to adjust the contrast of the mammograms through use of image processing. While it is possible to improve visibility of calcifications through increasing the spatial resolution, spatial resolution is not the sole factor influencing the visibility of lesion. Contrast resolution is also important in some instances for diagnosing calcifications and the other small features in the image through manipulating the contrast resolution. Several studies have demonstrated that despite the limited spatial resolution, the visibility of calcifications on DM is not significantly different from that on SFM (1 6). In addition, the pixel sizes in the ranges that are studied do not have a strong effect on the radiologists accuracy for the characterization of calcifications (3). Obenauer et al. reported that the flat-panel DM system was superior to SFM in image quality, detail visibility, image exposure and artifacts (6). They concluded that the better contrast detectability and the ability to do the image processing highly compensated for the limitations in spatial resolution. However, most previous reports have focused on comparing observer performance with using SFM and hard copy digital mammography (HCDM). The diagnostic accuracy of the hardcopy and softcopy interpretation is likely to be comparable if a high-resolution laser printer and a high quality workstation having high spatial and contrast resolution …