QC parameters that should be tested monthly include which of the following?

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

Answer: (C)

Monthly QC tests focus on parameters that drift slowly and benefit from looking at data gathered over weeks. The second and third checks fit that idea because they reflect overall system stability and image consistency across multiple exposures and time, so a month’s worth of data helps reveal trends and ensure reliable performance. The first parameter, by contrast, is typically more sensitive to immediate changes or directly influences dose or image quality on a day-to-day basis, so it needs to be verified more frequently than monthly. Therefore, the items that belong in the monthly set are the second and third checks.