Remnant radiation is the radiation that forms the radiographic image after passing through the patient.

• A. Primary beam
• B. Remnant radiation
• C. Scattered radiation
• D. Leakage radiation

Answer: (B)

Remnant radiation is the radiation that forms the radiographic image because it consists of the photons that exit the patient and travel to the image receptor. As the primary beam passes through tissues, many photons are absorbed or scattered, but the ones that make it through (including both transmitted primary photons and those scattered but still directed toward the detector) reach the receptor and carry the image information. The primary beam is the original radiation before it interacts with the patient, so it does not form the image on its own. Scattered radiation contributes to image fog and patient dose but is not the primary source that creates the image, and leakage radiation is stray radiation escaping the tube housing, not the image-forming remnant.