What causes radiographic magnification?

What causes radiographic magnification?

• A. Divergent X-ray beams cause magnification
• B. Increased receptor sensitivity
• C. The use of digital sensors only
• D. Higher patient bone density

Answer: (A)

Magnification in radiography happens because X-ray beams diverge from the focal spot. When the object sits between the source and the image receptor, the diverging rays make the projection on the receptor larger than the actual object. The amount of magnification depends on geometry: the magnification factor M is SID divided by SOD (source-to-image distance over source-to-object distance). Keeping the object closer to the receptor and increasing the distance from the source to the receptor reduces magnification. Receptor sensitivity, digital vs film sensors, or bone density do not determine magnification; they affect exposure or image quality, not the geometric size of the image.

Magnification in radiography happens because X-ray beams diverge from the focal spot. When the object sits between the source and the image receptor, the diverging rays make the projection on the receptor larger than the actual object. The amount of magnification depends on geometry: the magnification factor M is SID divided by SOD (source-to-image distance over source-to-object distance). Keeping the object closer to the receptor and increasing the distance from the source to the receptor reduces magnification. Receptor sensitivity, digital vs film sensors, or bone density do not determine magnification; they affect exposure or image quality, not the geometric size of the image.