What is the effect of the "heel effect" in an x-ray tube?

The "heel effect" refers to the variation in x-ray beam intensity across the x-ray field, resulting from the geometry of the x-ray tube and the positioning of the anode and cathode. In an x-ray tube, the cathode side (the side where the electrons are emitted from the filament) produces a higher intensity of x-rays compared to the anode side. This happens because x-rays emitted from the cathode side have a shorter path to travel to the patient or imaging receptor, while those from the anode side must pass through the anode material itself.

As a result, the x-rays generated on the cathode side are more intense, leading to a higher exposure in this area. This effect can be utilized in positioning the x-ray beam to ensure that denser body parts, which may absorb more radiation, are aligned with the higher intensity side of the beam, allowing for better imaging of anatomical structures.

The other choices do not accurately describe the heel effect. The uniformity of intensity is not characteristic of the heel effect, and the statement about intensity on the anode side contradicts the fundamental understanding of how beam intensity varies due to the tube design. The last option about intensity being reduced at the edges is also misleading