What is the purpose of the anode heel effect in clinical imaging?

• A. Increases the overall exposure across the image.
• B. Causes a slight variation in exposure across the image; positioning the tooth toward the cathode side can mitigate effects.
• C. Eliminates scatter radiation.
• D. Increases patient dose uniformly.

Answer: (B)

The anode heel effect causes a small variation in beam intensity across the X-ray field due to the geometry and absorption in the anode target. The part of the beam toward the cathode side is more intense, while the portion toward the anode side is less intense.

In clinical imaging, this gradient can be used to improve image uniformity. By orienting the tooth so that the thicker or more attenuating part sits toward the cathode side, the higher intensity there helps compensate for the greater attenuation, producing more uniform exposure across the image and better contrast in the thicker region.

The other ideas aren’t accurate: the heel effect does not increase exposure across the image or patient dose uniformly, nor does it eliminate scatter radiation.