According to the notes, at kVp between 50 and 70, the specified measurement in millimeters is 1.5.

According to the notes, at kVp between 50 and 70, the specified measurement in millimeters is 1.5.

• A. 2.0
• B. 1.0
• C. 1.5
• D. 2.5

Answer: (C)

Filtration in dental x-ray beams is specified in millimeters of aluminum and serves to remove low-energy photons, hardening the beam so more of the useful, penetrating photons reach the image receptor while reducing patient dose. For kVp in the 50–70 range, the standard total filtration is 1.5 mm Al. That’s why 1.5 is the correct specification here. The other values don’t match this typical guideline: 2.0 mm Al isn’t the standard for this kVp band, 1.0 mm Al would under-filtrate the beam at this range, and 2.5 mm Al is generally used for higher kVp levels where even more filtration is required. Increasing filtration reduces patient dose but may require adjusting exposure factors to maintain image receptor exposure.

Filtration in dental x-ray beams is specified in millimeters of aluminum and serves to remove low-energy photons, hardening the beam so more of the useful, penetrating photons reach the image receptor while reducing patient dose. For kVp in the 50–70 range, the standard total filtration is 1.5 mm Al. That’s why 1.5 is the correct specification here. The other values don’t match this typical guideline: 2.0 mm Al isn’t the standard for this kVp band, 1.0 mm Al would under-filtrate the beam at this range, and 2.5 mm Al is generally used for higher kVp levels where even more filtration is required. Increasing filtration reduces patient dose but may require adjusting exposure factors to maintain image receptor exposure.