What is the FFD for a medial oblique ankle X-ray?

The focus-to-film distance (FFD), more commonly referred to as the source-to-image distance (SID), is a crucial measurement in radiography that helps ensure the quality and clarity of the images obtained. For a medial oblique ankle X-ray, an FFD of 40 inches is standard.

This distance allows for an adequate geometric representation of the ankle joint while minimizing distortion and maximizing image sharpness. At 40 inches, the X-ray beam is able to penetrate the area of interest effectively, while the distance also helps reduce radiation dose to the patient compared to shorter distances.

In practice, using a 40-inch FFD is common in most limb radiography, striking a balance between achieving sufficient detail for diagnostic purposes and keeping patient exposure to radiation at a minimum. This standard has been established based on extensive research and practical experience in the field, allowing radiologists and technicians to rely on it for consistent and quality imaging results.