Image Quality of a Photon-Counting Mammography System Compared to Digital Mammography Based on Amorphous Silicon with CsI-Scintillator

摘要

To compare image quality and dose of a photon-counting multi-slit scanner (PC) and a system based on amorphous silicon (aSi), images of the CDMAM 3.4 were taken in standard mode. For 3cm PMMA, the PC used 29kV/11.7mAs, aSi used 27kV/ 50mAs. For 5cm PMMA, PC used 35kV /14.8mAs, aSi used 31kV/ 50 mAs. Exposure was manually increased for PC and lowered for aSi-system. Average glandular dose and an image quality index (IQI) were calculated over the diameter ranges 0.06 - 2.0mm and 0.1-1. In standard mode with 3cm PMMA, IQI for PC was 35% lower than for aSi at 80% lower dose. Increased dose of PC resulted in 13% lower IQI at 57% lower dose. With 5cm PMMA IQI in standard mode was 18 % lower with PC at a 69% lower dose. Increasing the dose of PC resulted a 7% lower IQI at 54% lower dose. In conclusion the PC-system might reduce dose by up to 54% at equivalent image quality, although maximal quality of aSi could not be reached.