How does decreasing filtration thickness affect the quantity of the x-ray beam?

• A. Decreased quantity
• B. Increased quantity
• C. No change
• D. Variable quantity

Answer: (B)

Filtration acts as an absorber for the x-ray beam. When you decrease filtration thickness, there’s less material to absorb photons, so more photons pass through the filter and exit the tube. That increases the beam quantity (the number of photons per unit area per unit time). It’s also worth noting that removing filtration shifts the spectrum toward more low-energy photons, which lowers the beam’s average energy (quality) and can raise patient dose, but the immediate effect on quantity is an increase.