Which type of X-ray photons are preferentially removed by filtration?

Which type of X-ray photons are preferentially removed by filtration?

• A. characteristic photons
• B. scattered photons
• C. high energy photons
• D. low energy photons

Answer: (D)

Filtration cleans up the beam by removing the photons that carry little useful information but add dose to the patient. These are the low-energy photons, which are absorbed much more readily by the filter material than higher-energy photons. Because the filter attenuates low-energy photons more effectively, the beam that emerges is “harder” with a higher average energy. High-energy photons pass through relatively easily, so they aren’t removed as much. Filtration isn’t specifically targeting characteristic photons or scattered photons; it’s about trimming the low-energy portion of the spectrum to improve image quality and reduce patient dose.

Filtration cleans up the beam by removing the photons that carry little useful information but add dose to the patient. These are the low-energy photons, which are absorbed much more readily by the filter material than higher-energy photons. Because the filter attenuates low-energy photons more effectively, the beam that emerges is “harder” with a higher average energy. High-energy photons pass through relatively easily, so they aren’t removed as much. Filtration isn’t specifically targeting characteristic photons or scattered photons; it’s about trimming the low-energy portion of the spectrum to improve image quality and reduce patient dose.