Radiation that emerges from the patient after attenuation is called

• A. Exit radiation
• B. Transmitted radiation
• C. Scattered radiation
• D. Leakage radiation

Answer: (A)

When the x-ray beam passes through the patient, tissues absorb or scatter many photons. The photons that emerge from the patient and travel toward the image receptor are called exit radiation (also known as remnant radiation). This is the radiation that remains after attenuation and is what actually contributes to forming the radiographic image. It encompasses photons that pass straight through (transmitted) as well as those that have been scattered inside the patient but still exit toward the receptor. Leakage radiation, by contrast, comes from the x-ray tube housing and not from the patient, and scattered radiation refers specifically to photons that have changed direction inside the patient. So the radiation that emerges from the patient after attenuation is exit radiation.