Which major interaction predominates in the diagnostic x-ray range?

Which major interaction predominates in the diagnostic x-ray range?

• A. Compton scatter
• B. Photoelectric effect
• C. Bremsstrahlung
• D. Coherent/Classical

Answer: (A)

In diagnostic-range X-rays (roughly 20–120 keV), Compton scattering is the main way photons interact with matter. At these energies, photons are more likely to collide with loosely bound or free electrons in tissue, scattering and transferring part of their energy in the process. The probability of this Compton interaction remains higher than that of the photoelectric effect for the common tissues we image, especially as energy climbs within the diagnostic range. The photoelectric effect, while dominant at very low energies or with high-Z materials, falls off quickly with energy and is less likely in soft tissue. Coherent (classical) scattering occurs but has a relatively small probability at diagnostic energies, and Bremsstrahlung refers to X-ray production in the tube, not to how X-rays interact with matter once emitted.

In diagnostic-range X-rays (roughly 20–120 keV), Compton scattering is the main way photons interact with matter. At these energies, photons are more likely to collide with loosely bound or free electrons in tissue, scattering and transferring part of their energy in the process. The probability of this Compton interaction remains higher than that of the photoelectric effect for the common tissues we image, especially as energy climbs within the diagnostic range. The photoelectric effect, while dominant at very low energies or with high-Z materials, falls off quickly with energy and is less likely in soft tissue. Coherent (classical) scattering occurs but has a relatively small probability at diagnostic energies, and Bremsstrahlung refers to X-ray production in the tube, not to how X-rays interact with matter once emitted.