Consider the task of identifying a 1 cm thick breast cancer that is embedded inside a 4.2 cm thick fibroglandular breast as depicted in Fig.

The cancerous tumor has a cross-sectional area of A=1 mm . Let us assume the beam is monoenergetic with photons of energy 20 keV. The total linear attenuation coefficients for the breast cancer and fibroglandular breast tissue at 20 keV are respectively µcancer=0.844 cm^-1
and µfibroglandular=0.802 cm^-1.

First let's consider the case with no scatter at image receptor. Calculate the local radiographic contrast [i.e. C=|Nt-Nb|/Nb] for this particular imaging task.

Next, suppose that there was a constant S/P = 3 at the image receptor. Calculate the local radiographic constrast as in I but now including the scatter contribution.