Imaging performance of a prototype scanned-slot digital mammography system

摘要

Abstract: A prototype of a clinical scanned-slot digital mammography imaging system has been developed, which demonstrates better contrast sensitivity and latitude than current state-of-the-art film-screen mammography systems. The detector consists of a Gd$- 2$/O$-2$/S:Tb phosphor screen coupled via a 2-to-1 demagnifying fiber-optic taper to two time-delay integration (TDI) charge- coupled device (CCD) image arrays. Images are obtained by scanning the 4.0 mm wide by 21 cm long detector across the image field. An 18 cm by 21 cm image contains 2900 by 4032 pixels, of dimension 62 $mu@m $MUL 52 $mu@m at the detector. Currently, images are produced in 7.8 seconds using a 40 kV tungsten-target spectrum with a total heat load of 50 kJ, giving a mean glandular dose of 0.85 mGy (85 mrad) to a 5 cm thick 50% glandular, 50% adipose breast. The detector has a limiting resolution of 9.5 lp/mm. A clinical version of this prototype, which incorporates several improvements, is being constructed.!35