Automatic Exposure Control Devices for Digital Mammography

摘要

Purpose: The broad, long-term objective of this IDEA proposal is to achieve optimized image quality for DM within acceptable limits of radiation exposure by developing innovative approaches for controlling DM exposures. Scope: This project's specific aims are (1) to use short, low dose pre-exposures of the breast to create 'intelligent' regions of interest that determine the exposure parameters for the fully exposed image; and (2) to select exposure parameters (mAs, kVp, and beam filtration) based on 'intelligent decisions' that optimize signal-to-noise (SNR) as a function of mean glandular dose. Major Findings & Results: Complete analysis of beam optimization for digital mammography and mean glandular dose measurements have been completed. Software has been developed for analysis of digitally acquired mammograms allowing the area greatest radiographic attenuation (the ECROl) to be selected and the pixel variance in the ECROl to be analyzed. We are currently completing running our analysis tools using digital mammograms obtained from breasts with a variety of compositions and sizes. We will evaluate the effect of radiographic heterogeneity on the selection of the ECROl, as well as possible spurious results from m icrocalcification clusters or cysts. Significance: We have implemented an early version of automatic exposure control device that will be refined over the remaining 6 months of funding. Results from a pilot evaluation demonstrate that the AEC produces digital images of higher quality than current conventional mammography at similar or reduced mean glandular radiation doses.