Filters in an X-ray tube are used to

• A. Increase X-ray intensity
• B. Shield operator
• C. Reduce X-ray production
• D. Modify energy spectrum of released X-rays

Answer: (D)

Filters in an X-ray tube shape the energy spectrum of the emitted X-rays by absorbing low-energy photons. This hardens the beam, raising the average photon energy, which lowers patient dose and improves image quality by reducing the influence of soft photons that don’t contribute effectively to image formation. Filtration does not increase X-ray intensity; it reduces the total number of photons reaching the patient. It is not intended to shield the operator—the primary shielding comes from barrier materials and protective gear around the workspace. It also does not reduce how much X-ray is produced at the source—the tube still generates X-rays according to the exposure settings; filtration simply removes some photons after production.