Which factors influence the quantity of scattered radiation?

• A. kVp, Field Size, Part Thickness, and Tissue Density
• B. kVp, Field Size, Part Thickness
• C. Field Size and Part Thickness
• D. Tissue Density only

Answer: (B)

The amount of scattered radiation depends on how much tissue is irradiated and how energetic the beam is. Increasing kVp raises the beam’s energy, which increases the likelihood of Compton interactions that produce scatter and also leads to more high-energy photons escaping the patient. Widening the field size exposes more tissue to the beam, so more scatter is generated overall. Increasing the part thickness lengthens the path photons travel through tissue, providing more opportunities for scattering.

Density of tissue affects interaction probability, but it’s not treated as an independent, controllable factor in this context—the effect of density is encompassed by the tissue’s thickness and type. So the factors that best describe the quantity of scattered radiation are kVp, field size, and part thickness.