Explain what is meant by the Compton effect when X-ray photons interact with matter.
The diagram below shows a parallel beam of X-rays incident normally on some liver tissue.
The linear attenuation coefficient of the liver tissue is 0.18 cm-1. The intensity of the incident beam is 4.5 × 103 W m-2. There is a small calcified nodule at a depth of 8.5 cm from the surface of the liver tissue. The cross-sectional area of the nodule normal to the beam is 1.6 × 10-4 m2.
The beam is switched on for 18 s.
Calculate the total X-ray energy incident on the nodule in this period of 18 s.
Conventional planar X-ray imaging was unable to clearly resolve this nodule because the attenuation coefficients of the nodule and the surrounding liver tissue were very similar under standard diagnostic energies.
Name an alternative medical imaging technique utilizing X-rays that can resolve this issue, and explain how it achieves a clearer image.
