Directing the anode side of the x-ray field toward the toes during an AP projection of the foot results in which outcome?

Directing the anode side of the x-ray field toward the toes during an AP projection of the foot results in which outcome?

• A. More uniform receptor exposure
• B. Increased exposure on the toes only
• C. No change in exposure
• D. Decreased receptor exposure

Answer: (A)

The key idea here is the anode heel effect: the x-ray beam is more intense at the cathode end and weaker at the anode end. In an AP foot, the heel is thicker than the toes, so you want that thicker part to lie where the beam is strongest to balance the exposure across the foot. Directing the anode side toward the toes places the toes on the weaker (anode) end and the heel on the stronger (cathode) end, which helps compensate for the thickness differences and yields a more uniform receptor exposure across the entire foot. If you did the opposite, the toes would receive comparatively less exposure and the image would be more nonuniform.

The key idea here is the anode heel effect: the x-ray beam is more intense at the cathode end and weaker at the anode end. In an AP foot, the heel is thicker than the toes, so you want that thicker part to lie where the beam is strongest to balance the exposure across the foot. Directing the anode side toward the toes places the toes on the weaker (anode) end and the heel on the stronger (cathode) end, which helps compensate for the thickness differences and yields a more uniform receptor exposure across the entire foot. If you did the opposite, the toes would receive comparatively less exposure and the image would be more nonuniform.