What is the test device used for the X-ray Beam, Bucky Motion and Centering?

• A. Dosimeter
• B. Aluminum sheets
• C. Homogeneous phantom and lead strips
• D. Lead apron

Answer: (C)

Testing beam geometry, bucky motion, and centering needs a setup that makes both the uniformity of the exposure and the exact alignment visible. A homogeneous phantom provides uniform attenuation, so any irregularity in the radiograph is due to setup rather than patient anatomy. The added lead strips create a clear, high-contrast reference pattern on the image. By radiographing this combination, you can see whether the central ray is truly centered on the image receptor and whether the bucky tray movement maintains that alignment throughout the exposure. If the beam were off-center or the bucky wasn’t moving correctly, the lead strips would appear displaced or asymmetric relative to the phantom’s uniform background, signaling an alignment or centering issue. In contrast, a dosimeter measures exposure dose, aluminum sheets test filtration, and a lead apron protects the patient; none of these directly verify beam centering and bucky motion.