Which interaction between x-ray photons and matter involves the most potential radiation hazard to personnel?

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

Answer: (C)

Compton scatter presents a significant potential radiation hazard to personnel because it involves the interaction of x-ray photons with the outer-shell electrons of atoms, resulting in the emission of scattered photons and recoil electrons. This interaction not only creates scattered radiation that can expose radiologic staff, but also involves the transfer of energy, which can lead to ionization and secondary radiation production, further increasing the exposure risk.

In environments where x-ray imaging is performed, Compton scatter is a dominant form of interaction for diagnostic imaging energies, making it a common occurrence. As x-ray photons scatter in various directions, they contribute to the overall radiation dose experienced by personnel, particularly those working in close proximity to the patient or imaging equipment.

While the photoelectric effect is significant in terms of imaging contrast and patient dose, it primarily involves the absorption of photons, thus not posing the same level of secondary hazard to personnel. Similarly, coherent scatter primarily occurs at low energies and involves elastic scattering with no energy transfer, resulting in minimal risk. Pair production, although pertinent at very high energies, is less relevant in typical diagnostic radiography scenarios and requires energies above 1.02 MeV. Therefore, Compton scatter is crucial in understanding the potential radiation hazards for personnel in radiological procedures.