Which choices correctly identify the factors that determine the quantity of scatter radiation?

• A. kVp
• B. Part thickness
• C. Field size
• D. All of the above

Answer: (D)

Scatter quantity is driven by three factors: the beam energy, how much tissue is irradiated, and how large the beam is. When kVp increases, photons have higher energy and are more likely to undergo Compton scattering, so more scatter is produced. Greater part thickness means more tissue for photons to interact with, providing more opportunities for scattering. A larger field size irradiates more tissue, increasing the total number of scattering events and the amount of scatter that exits toward the image receptor. Because all three elements raise the amount of scattered radiation, the correct choice is that all of them determine the scatter quantity.