What is the primary effect of filtration in diagnostic radiography?

• A. Removes low-energy photons, reducing skin dose and improving beam quality.
• B. Increases beam intensity to improve image brightness.
• C. Improves image sharpness by altering focal spot size.
• D. Has no effect on patient dose.

Answer: (A)

Filtration removes low-energy photons from the x-ray beam. Those soft photons are absorbed by superficial tissues and contribute little to image formation, so removing them lowers the patient’s skin dose. At the same time, removing these photons makes the beam harder, increasing its average energy (beam quality), which improves penetration and image quality for the same receptor exposure. So the primary effect is reducing patient dose while enhancing beam quality.

The other ideas don’t fit: filtration doesn’t increase beam intensity, it doesn’t alter the focal spot to improve sharpness, and it does affect dose (it reduces it), so claiming no dose effect isn’t correct.