The part of the X-ray beam that has gone through the patient and reaches the film is called?

• A. Incident radiation
• B. Remnant radiation
• C. Scattered radiation
• D. Leakage radiation

Answer: (B)

Remnant radiation is the beam that exits the patient and reaches the image receptor. It consists of transmitted primary photons that passed through the body and any photons scattered inside the tissue that escape toward the film. This exit beam is the radiation that actually forms the radiographic image. The original tube beam before it hits the patient is incident radiation, and leakage radiation is the radiation that escapes from the X-ray tube housing. Scatter within the patient contributes to remnant radiation but by itself isn’t the term used for the exiting beam.