The X-ray at the center of the beam is called what?

• A. Central Ray
• B. Peripheral Ray
• C. Exit Dose
• D. Exposure Button

Answer: (A)

The central ray is the X-ray beam’s center line, the straight path that passes through the center of the image receptor and the part of interest in the patient. Aligning this central ray with the anatomy ensures the exposure is distributed correctly and the image has proper sharpness and contrast. The other terms describe different things: peripheral rays are the outer parts of the beam, not the center; exit dose refers to radiation that exits the patient after attenuation, not the beam’s center; and the exposure button is just the switch used to start the exposure.