In a clavicle radiograph, switching from AP to PA projection increases spatial resolution primarily due to which factor?

In a clavicle radiograph, switching from AP to PA projection increases spatial resolution primarily due to which factor?

• A. Increased source-to-image distance (SID)
• B. Smaller focal spot size
• C. Decreased object-to-image distance (OID)
• D. Higher tube voltage

Answer: (C)

Spatial resolution in radiography is limited by geometric unsharpness, which grows with the distance between the object and the image receptor. When the object is closer to the detector, the rays create less blur around edges, yielding a crisper image. Switching from AP to PA for a clavicle brings the clavicle closer to the image receptor, reducing the object-to-image distance. That smaller distance reduces geometric blur, improving spatial resolution. The other factors like focal spot size, SID, or tube voltage aren’t the primary drivers of this change in this scenario; tube voltage mainly affects contrast, and SID or focal spot size would have a smaller effect here.

Spatial resolution in radiography is limited by geometric unsharpness, which grows with the distance between the object and the image receptor. When the object is closer to the detector, the rays create less blur around edges, yielding a crisper image.

Switching from AP to PA for a clavicle brings the clavicle closer to the image receptor, reducing the object-to-image distance. That smaller distance reduces geometric blur, improving spatial resolution. The other factors like focal spot size, SID, or tube voltage aren’t the primary drivers of this change in this scenario; tube voltage mainly affects contrast, and SID or focal spot size would have a smaller effect here.