The cancerous tumor has a cross-sectional area of
A=1 mm2. 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.
I. 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.
II. 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.
A patient lying down on his back is imaged with an x-ray tube. The slope of the anode is 12degrees. The actual focal spot size is 2 mm by 2 mm. The source to chest distance is 100 cm. One embedded structure of 4 mm width is at a depth of 4 cm while another is of 2 mm width at 8 cm depth.
(a) Calculate the size of both structures at the image plane which is located 10 cm below the patient’s back.
(b) Calculate the size of the blurred regions of the image sections of
the embedded structures.