Which major interaction between x-ray photons and tissue cells poses a radiation hazard to personnel?

Which major interaction between x-ray photons and tissue cells poses a radiation hazard to personnel?

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

Answer: (A)

The main idea is that staff exposure in diagnostic radiology comes primarily from photons that scatter off the patient. In tissue at typical diagnostic energies, Compton scattering is the dominant interaction: an incoming x-ray photon collides with a loosely bound outer electron, ejects it, and continues with reduced energy in a new direction. The scattered photon can escape the patient and travel toward coworkers or room occupants, creating external exposure. The recoil electron contributes to dose inside the patient, but it’s the scattered photon field from Compton interactions that drives occupational hazards. The other interactions are less relevant for external exposure in this context. The photoelectric effect mainly increases absorbed dose within the patient (and is more pronounced with high-Z materials). Bremsstrahlung describes radiation produced in the tube rather than a tissue interaction that creates scatter at the patient, and coherent (Rayleigh) scattering occurs mainly at very low energies and is negligible for typical diagnostic radiology exposure.

The main idea is that staff exposure in diagnostic radiology comes primarily from photons that scatter off the patient. In tissue at typical diagnostic energies, Compton scattering is the dominant interaction: an incoming x-ray photon collides with a loosely bound outer electron, ejects it, and continues with reduced energy in a new direction. The scattered photon can escape the patient and travel toward coworkers or room occupants, creating external exposure. The recoil electron contributes to dose inside the patient, but it’s the scattered photon field from Compton interactions that drives occupational hazards.

The other interactions are less relevant for external exposure in this context. The photoelectric effect mainly increases absorbed dose within the patient (and is more pronounced with high-Z materials). Bremsstrahlung describes radiation produced in the tube rather than a tissue interaction that creates scatter at the patient, and coherent (Rayleigh) scattering occurs mainly at very low energies and is negligible for typical diagnostic radiology exposure.