Which of the following are used for annual testing of X-ray system filtration (HVL): 1) dosimeter 2) type 1100 aluminum sheets 3) semi-log graph paper

• A. 1 and 2
• B. 1 and 3
• C. 2 and 3
• D. 1, 2 and 3

Answer: (D)

HVL testing relies on measuring how the X-ray beam is attenuated by known amounts of filtration. To do this, you need a detector to quantify beam intensity, a set of standardized aluminum filters to create precise attenuation steps, and a plotting method that makes the exponential relationship easy to read. A dosimeter or ionization chamber gives you the actual exposure values for the unfiltered beam and after each aluminum step. The type 1100 aluminum sheets provide the exact thickness increments you insert to create those attenuation steps. Then you plot the logarithm of the measured exposures against the aluminum thickness on semi-log graph paper; the resulting straight line lets you determine the HVL—the thickness where the beam intensity drops to half of its original value. This combined approach directly measures beam quality and ensures that filtration meets safety and regulatory requirements.