Application of DQE for quantitative assessment of detectors to estimate AEC efficiency in digital mammography

Optimisation of the detector’s exposure parameters settings for image quality and patient dose is an important task in digital mammography. Assessment of a digital detector’s performance can be done objectively and without operator bias by determining the Detective Quantum Efficiency (DQE). The authors of this article aim to prove that the performance of the AEC system can be objectively portrayed through DQE. The results were examined for influence of KAD changes on DQE values and to determine if it was possible to obtain similar DQE values for different exposures. While analysing the effect of the operation of the AEC system described with DQE, the doses received by women during mammography examinations were considered, as well.

The AEC system’s exposure control mechanism cannot guarantee the same DQE value for different object thicknesses. When the object thickness increases, the AEC system should increase the KAD value to obtain the same DQE value. The result of increasing KAD would be the increase of mean glandular dose for some women. However, assuming that DQE is a good indicator of image quality, introducing the proposed changes to the AEC system’s operation would result in the same image quality for all breast thicknesses.

This approach to DQE use for AEC system evaluation is independent of the image processing procedure and can be the basis for changes to system calibration done by the manufacturer’s technical support team.