1. A breast tomosynthesis method comprising: acquiring tomosynthesis projection x-ray images T(p,n) of a phantom, where the index p designates a respective one of a first multiplicity of P first projection angles of an x-ray beam relative to the phantom, p=1, 2, 3,. .. , P, the index n designates the number of projection images taken at a given one of the first projection angles, and n≧2; generating enhanced gain maps EG(p′), where the index p′ designates a respective one of a second multiplicity of P′ second projection angles of an x-ray beam relative to a patient's breast and p′=1, 2, 3,. .. , P′, in a computer-implemented process combining parameters derived from said images T(p,n); acquiring tomosynthesis x-ray images T′(p′) of a patient's breast at said second projection angles; gain-correcting the tomosynthesis x-ray images T′(p′) of the patient's breast using the enhanced gain maps EG(p′) in a computer-implemented process to thereby produce gain-corrected breast images; and further computer-processing said gain-corrected breast images and displaying breast images resulting from said further computer-processing.