Backscatter radiation originates from where in the radiographic setup?

• A. Radiation from the tube housing
• B. Backscatter from the patient and surrounding surfaces
• C. Radiation from the image receptor
• D. Radiation from the surrounding room walls

Answer: (B)

Backscatter radiation is the portion of the X-ray beam that, after interacting with matter, travels back toward the incident side. In radiography, this mainly comes from the patient: photons undergo scattering in tissue (primarily Compton scattering) and some of those scattered photons are directed toward the image receptor, adding exposure and reducing contrast. Photons can also scatter off surrounding surfaces such as the table, supports, and room walls, reflecting back toward the receptor and contributing to the backscatter. It is not leakage from the tube housing or emission from the image receptor. So the origin is the patient and the surrounding surfaces.