Effect of anode/filter combination on the dose and image quality of a digital mammography system based on an amorphous selenium detector

A comparison of image quality and glandular breast dose was carried out on two digital mammography systems using alpha-Se flat panel detectors. The two digital mammography systems currently available from Hologic were compared. The original system utilises Mo /Mo and Mo/Rh as target/filter combinations, while the new system uses W/Rh and W/Ag. Images of mammography phantoms with different simulated breast thickness and various glandular compositions, was calculated and the AGD needed to visualize a detail with a CNR of 5 was estimated. For each phantom thickness and target/filter combination, there is an optimum voltage which maximizes the AGD. Using the Tungsten tube system there is a dose redcution of 16% at 4cm and 5cm, and 35% for 6 cm compared with the dose needed with the Mo/Mo combination.