We use a contrast-detail observer study to compare performance of a novel 3D computed mammotomography (CmT)
system with a commercially developed full-field digital mammography (FFDM) system. A contrast-detail phantom
comprised of uniform acrylic spheres of various diameters was developed and placed in a variety of mediums
including uniform water (simulating low contrast lesions within a uniform background), water and acrylic yarn
(simulating low contrast lesions with over/under-lying structure), oil only (simulating higher contrast lesions in a
uniform background), and oil and acrylic yarn (simulating higher contrast lesions with over/under-lying structure).
For CmT, the phantom was placed in a 14.6 cm diameter uncompressed breast phantom and projections acquired using
a simple circular orbit, W-target tube, 60 kVp tube potential, 0.05 cm Ce filtration, 4 mAs per projection, and a CsI(Tl)
digital x-ray detector. Reconstructions used an iterative OSTR algorithm. For FFDM, the phantom was placed in a
5.3-cm-thick compressed breast phantom. Single CC-view mammograms were acquired using a clinical W-target tube
with 50 um Rh filtration, 28 kVp, photo-timed mAs per our clinical mammography operation, and a Selenium-based
flat-panel detector (Mammomat Novation, Siemens). Six observers evaluated the images in terms of the number of
detectable spheres. FFDM performed significantly better for the low contrast lesions in uniform water background
(p<0.05). However, CmT performed significantly better for all other cases (p<0.05). Results indicate that CmT shows
significant advantage in soft tissue detection over FFDM in otherwise low contrast dense breasts.