Technological improvements in mammography over the past 20 years.

During the past twenty years many significant technological improvements in mammographic X-ray equipment and screen-film-processing systems have occurred. Today it is possible to obtain mammograms with higher image quality at a significantly lower radiation dose compared to mammograms dating back about 20 years. In this review article, X-ray spectra, limiting geometric resolution, characteristic (H & D) curves, modulation transfer function (MTF) and noise power spectra (NPS) are used to demonstrate technological improvements in mammographic screen-film image quality.