Automated Area Beam Equalization Mammography for Improved Imaging of Dense Breast
Abstract
In mammography, dense breast regions persistently suffer from reduced contrast-to-noise ratio (CNR) because of degraded contrast from large scatter intensities and relatively high noise. Area x-ray beam equalization can improve image quality by increasing the x-ray exposure to under-penetrated regions without increasing the exposure to other breast regions. Optimal equalization parameters with respect to image quality and patient dose were determined through computer simulations and validated with experimental observations on a step phantom and an anthropomorphic breast phantom. The parameters important in equalization digital mammography were considered: attenuator material (Z=13 to 92), beam energy (22 to 34 kVp), and equalization level. A Mo/Mo digital mammography system was used for image acquisition. A prototype 16x 16 piston driven equalization system was used for preparing patient-specific equalization masks. Simulation studies showed that a molybdenum attenuator, a tube voltage of approximately 26-2g kVp, and an equalization level of 20 were optimal for improving contrast, CNR, and figure of merit (FOM=CNR exp 2/exposure). Experimental measurements using these parameters showed significant improvements in contrast, CNR, and FOM. Moreover, equalized images of a breast phantom showed improved image quality. These results indicate that area beam equalization can improve image quality in digital mammography.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2004
- Accession Number
- ADA431975
Entities
People
- Sabee Molloi
Organizations
- University of California, Irvine