What is the recommended source-to-image distance (SID) for lateral calcaneus radiographs?

What is the recommended source-to-image distance (SID) for lateral calcaneus radiographs?

• A. 50 inches (127 cm)
• B. 40 inches (102 cm)
• C. 60 inches (152 cm)
• D. 30 inches (76 cm)

Answer: (B)

Source-to-image distance affects how large the heel appears and how sharp the image will be. For a lateral calcaneus view, forty inches is used because it provides enough detail to see the bone surfaces and any fracture lines without excessive magnification. A shorter distance would magnify the calcaneus more, distorting anatomy and reducing detail. A longer distance would reduce magnification further but would require higher exposure to maintain image brightness and isn’t typically needed for this view. So, forty inches is the standard SID for this projection.

Source-to-image distance affects how large the heel appears and how sharp the image will be. For a lateral calcaneus view, forty inches is used because it provides enough detail to see the bone surfaces and any fracture lines without excessive magnification. A shorter distance would magnify the calcaneus more, distorting anatomy and reducing detail. A longer distance would reduce magnification further but would require higher exposure to maintain image brightness and isn’t typically needed for this view. So, forty inches is the standard SID for this projection.