Which of the following statements about filtration and patient dose is most accurate?

• A. Increases patient dose
• B. Decreases patient dose
• C. No change to patient dose
• D. Depends on tube voltage

Answer: (B)

Filtration removes the soft, low-energy photons from the X-ray beam before it reaches the patient. Those low-energy photons contribute to radiation dose but don’t improve image quality because they are absorbed in superficial tissues and don’t reach the detector effectively. By filtering them out, the patient’s absorbed dose is reduced while the beam’s average energy increases (beam quality improves). If you keep the same exposure settings, fewer photons reach the patient, so dose drops; in practice, you may adjust technique to maintain image density, but the overall effect of filtration is a decrease in patient dose. The other options don’t fit because filtration doesn’t increase dose or leave it unchanged; while the amount of reduction can vary with tube voltage, the most accurate general statement is that filtration decreases patient dose.