Abstract
The X-ray tomosynthesis that measures several low dose projections over a limited angular range has been investigated
as an alternative method of X-ray mammography for breast cancer screening. An extension of the scan
coverage increases the vertical resolution by mitigating the interplane blurring. The implementation of a wide
angle tomosynthesis equipment, however, may not be straightforward, mainly due to the image deterioration
from the statistical noise in exterior projections. In this paper, we adopt the voltage modulation scheme to
enlarge the coverage of the tomosynthesis scan. The higher tube voltages are used for outer angles, which offers
the sufficient penetrating power for outlying frames in which the pathway of X-ray photons is elongated. To
reconstruct 3D information from voltage modulated projections, we propose a novel algorithm, named information
theoretic discrepancy based iterative reconstruction (IDIR) algorithm, which allows to account for the
polychromatic acquisition model. The generalized information theoretic discrepancy (GID) is newly employed as
the objective function. Using particular features of the GID, the cost function is derived in terms of imaginary
variables with energy dependency, which leads to a tractable optimization problem without using the monochromatic
approximation. In preliminary experiments using simulated and experimental equipment, the proposed
imaging architecture and IDIR algorithm showed superior performances over conventional approaches.
