Which of the following is essential for the validity of follow-up bone densitometry scans?

• A. Different scanner models
• B. Changes in patient medication
• C. Same speed or mode of scanning
• D. Different positioning of the patient

Answer: (C)

For the validity of follow-up bone densitometry scans, it is crucial that the same speed or mode of scanning is used. This consistency in the scanning process ensures that the results are comparable over time. Variations in scanning speed or technique can introduce variability that might not be related to actual changes in bone density, but rather to differences in how the scans are performed. Consistent scanning parameters help in accurately assessing any changes in bone mineral density, which is fundamental for monitoring patient progress or the effectiveness of treatments.

Changes in scanner models, patient positioning, or medication can introduce factors that affect measurements, but ensuring the same scanning technique is applied is fundamental for making valid comparisons across different time points. This approach promotes reliability in assessing a patient's condition and aids in clinical decision-making.