What is the scanning pattern used with the pencil beam?

• A. Rectilinear
• B. Curvilinear
• C. Circular
• D. Angular

Answer: (A)

The pencil beam scanning pattern is characterized by its rectilinear motion, which means that it moves in straight lines during the scanning process. This method is used in dual-energy X-ray absorptiometry (DEXA) systems to measure bone density. By employing a pattern where the beam moves back and forth in parallel lines, it allows for precise measurements of bone mineral density at specific locations. The rectilinear pattern enhances the detail and accuracy of the measurement as it systematically scans the target area.

In contrast, other scanning patterns, such as curvilinear or circular, involve different trajectories that may not provide the same level of accuracy or detail in bone measurements. A curvilinear approach would involve a curved path that could introduce more variability in the results, while a circular scan would inherently limit the areas of measurement due to the rotational nature of the scan. Thus, the rectilinear pattern is specifically designed to optimize the ability to gather accurate and reliable data in bone densitometry.