Which X-ray interaction is responsible for the majority of scattered radiation reaching the film?

Which X-ray interaction is responsible for the majority of scattered radiation reaching the film?

• A. Coherent scattering
• B. Photoelectric effect
• C. Compton scatter
• D. Pair production

Answer: (C)

In diagnostic radiography, most scatter that reaches the film comes from Compton scattering. At typical clinical energies (roughly 60–120 kVp), photons interact with tissue electrons mainly through the Compton process, which deflects the photon and reduces its energy. The scattered photons emerge in many directions, including toward the film, contributing to image fog and blur. Coherent scattering occurs but is relatively rare at these energies and doesn’t contribute much to film exposure. The photoelectric effect involves absorption of photons by atoms, removing them from the beam rather than sending them to the film, and pair production requires energies well above diagnostic ranges. So the dominant source of scatter reaching the film is Compton scatter.

In diagnostic radiography, most scatter that reaches the film comes from Compton scattering. At typical clinical energies (roughly 60–120 kVp), photons interact with tissue electrons mainly through the Compton process, which deflects the photon and reduces its energy. The scattered photons emerge in many directions, including toward the film, contributing to image fog and blur. Coherent scattering occurs but is relatively rare at these energies and doesn’t contribute much to film exposure. The photoelectric effect involves absorption of photons by atoms, removing them from the beam rather than sending them to the film, and pair production requires energies well above diagnostic ranges. So the dominant source of scatter reaching the film is Compton scatter.