Method for dual-energy mammography

A method for dual-energy mammography, with the generation of a mammogram with two different radiation energies, characterized in that a comparison pattern with known distributions of density, thickness and effective atomic number, is disposed next to the breast;

• that on the basis of the mammograms of the comparison pattern, which have been generated at different energies, the parameters of the combination of the atomic number with the difference and with the ratio of the logarithms of the number of photons that flow through the breast without cooperating at two different radiation energies, are determined;
• and that based on the parameters of this combination, the distribution of the atomic number in the breast is displayed visually on the basis of the equation
• Z
• =
• 
• k
• α
• z
• 
• α
• +
• k
• β
• z
• 
• β
• +
• k
• 0
• z
• Z
• =
• k
• α
• z
• 
• (
• ln
• 
• N
• 0
• L
• N
• L
• -
• ln
• 
• N
• 0
• H
• N
• H
• )
• +
• k
• β
• z
• 
• ln
• 
• N
• 0
• L
• N
• L
• ln
• 
• N
• 0
• H
• N
• H
• +
• k
• 0
• z
• and the density based on the equation
• ρ
• =
• k
• α
• ρ
• 
• α
• +
• k
• β
• ρ
• 
• β
• +
• k
• 0
• ρ
• ρ
• =
• k
• α
• ρ
• 
• (
• ln
• 
• N
• 0
• L
• N
• L
• -
• ln
• 
• N
• 0
• H
• N
• H
• )
• +
• k
• β
• ρ
• 
• ln
• 
• N
• 0
• L
• N
• L
• ln
• 
• N
• 0
• H
• N
• H
• +
• k
• 0
• ρ
• in which
• Z is the effective atomic number and
• ρ is the effective density,
• α, β are correspondingly the difference α and the ratio β of the logarithms,
• N0 is the initial number of photons and
• N is the detected number of photons,
• L, H are indexes that designate the lower and the higher energy, respectively, and
• Kαz, kβz, k0z, kαρ, kβρ, k0ρ are linear coefficients.