How should the leg be positioned for a proximal femur scan?

• A. Externally rotated 10-15 degrees
• B. Internally rotated 15-25 degrees
• C. Perpendicular to the examination table
• D. Flexed at a 45-degree angle

Answer: (B)

For a proximal femur scan, positioning the leg internally rotated by 15-25 degrees is considered optimal for several important reasons. This specific positioning aligns the femoral neck parallel to the detector, which enhances the accuracy of bone density measurements. When the leg is internally rotated, it minimizes the geometric distortion that can occur during imaging, ensuring that the scan accurately reflects bone mineral density in the proximal femur region.

The internal rotation helps in achieving a clearer view of the femoral neck and greater trochanter, which are the primary areas of interest in a proximal femur scan. Accurately positioning the leg in this manner allows for standardized assessments across different patients, facilitating consistent interpretation of the results. Consistent positioning is crucial for the reliability of the diagnostic data obtained, particularly for follow-up scans to monitor changes in bone density over time.