Affiliations: Biomedical Engineering Department, The University of
Iowa, Iowa city, IA 52242, USA | Radiology Department, The University of Iowa, Iowa
city, IA 52242, USA | Hologic Inc., Bedford, MA 01730, USA | Electrical and Computer Engineering Department, The
University of Iowa, Iowa City, IA 52242, USA | VT-WFU School of Biomedical Engineering &
Science, Virginia Polytechnic Institute & State University, VA 24061,
USA
Abstract: Tomosynthesis was developed for mammography, especially breast
cancer detection. However, its limited-angular range scan and resultant data
incompleteness causes strong image artifacts and distortions. To address this
problem, a hybrid imaging method was proposed in our previous work, which
combines tomosynthesis and low-resolution CT into a single system to produce
fewer artifacts and distortions at a similar dose level. The purpose of this
paper is to evaluate the images reconstructed using the proposed method as
compared with that using the conventional tomosynthesis method (ML-convex). For
that purpose, the projection datasets are acquired in both numerical simulation
and phantom experiments on our breast imaging platform. Three kinds of phantoms
are used in our work, including a numerical phantom, a physical phantom and 8
in vitro phantoms made of breast specimens. In addition to visual
comparison of the reconstructed images, we employ spatial resolution, image
contrast, reconstruction error, and convergence rate to evaluate the results
quantitatively. It is observed that the results from our method can achieve
significantly higher spatial resolution, higher contrast, smaller
reconstruction error and faster convergence rate. Besides, a reader study using
8 in vitro phantoms of breast specimens demonstrates the clinical
potential of our method, which significantly outperforms the conventional
tomosynthesis.
Keywords: Cone-beam CT, tomosynthesis, mammography, breast imaging, image quality
