RADIATION not serving a purpose, which includes leakage and secondary radiation (scatter) is known as:

• A. Stray Radiation
• B. Direct Radiation
• C. Primary Radiation
• D. Secondary Radiation

Answer: (A)

Stray radiation is any radiation that does not serve a useful purpose in forming the image. It lies outside the intended useful beam and, importantly, includes both leakage from the x-ray tube housing and scatter produced when the primary beam interacts with the patient or objects in the room. This is why stray radiation is the best term here: it encompasses radiation that adds dose without helping image quality. The useful beam is the primary (direct) radiation that goes through the patient to the image receptor, while the scatter you get is a form of secondary radiation, but stray radiation specifically covers all unintended radiation outside the useful beam, including leakage and scatter.