Which statement correctly distinguishes inherent filtration from added filtration?

• A. Inherent filtration is placed in the beam path; added filtration is built into the tube or port.
• B. Inherent filtration is built into the tube or port; added filtration is placed in the beam path.
• C. Inherent filtration removes high-energy photons; added filtration removes low-energy photons.
• D. Inherent filtration is adjustable by the operator; added filtration is fixed.

Answer: (B)

The main idea is how filtration changes the beam by removing the low-energy photons that would just increase patient dose. Inherent filtration is built into the tube itself—inside the glass envelope and the housing—so it’s fixed and cannot be adjusted during a typical exam. Added filtration, on the other hand, is placed in the beam path after the tube (for example, as removable aluminum sheets between the collimator and the patient). It can be added or removed to adjust beam quality and dose.

Because the statement describes inherent filtration as built into the tube and added filtration as placed in the beam path, it correctly captures the two concepts. The other options misstate these relationships: filtration reduces low-energy photons, not high-energy ones; inherent filtration isn’t adjustable by the operator, while added filtration is adjustable.