Evaluation of resolution contrast, scatter/primary ratio and grid performance in mammography using breast phantoms and human breast tissue

Using measured experimental diffraction patterns obtained in our laboratory for human breast tissues (adipose and glandular) and six breast phantoms (water, lucite, nylon, 30% glandular-70% adipose, 50% glandular- 50% adipose and 70% glandular-30% adipose), we have evaluated the resolution contrast, scatter/primary ratio and grid performance for representative cases used in mammography. The diffraction patterns were obtained with a Molybdenum X-ray tube equipped with a graphite monochromator (17,4 keV) and a NaI detector. The attenuation coefficient of the substances was measured. The resolution contrast was defined as point spread functions. The obtained resolution contrasts are similar for all phantoms. Scatter/primary ratio are similar for glandular tissue and most of the breast phantom materials, the exception being Lucite and adipose tissue (more than 10% difference). The grid performance was calculated for a 5:1 ratio grid using the obtained diffraction patterns. The obtained grid performance for water and glandular tissue are clearly different from other breast phantoms and also from adipose tissue. Criteria for utilization of these phantoms were discussed. (author)