How does the heel effect impact x-ray intensity?

The heel effect is an important concept in x-ray imaging that describes how x-ray intensity varies across the radiation beam due to the geometry of the x-ray tube. Specifically, as x-rays pass through the anode of the tube, they become less intense on the anode side compared to the cathode side, primarily because the anode side of the beam has to pass through a thicker portion of the anode material.

When an x-ray beam is generated, the cathode side (where the electrons are emitted) typically has a higher intensity due to being closer to the source of the electrons. The heel effect leads to a decrease in intensity on the anode side because x-rays generated on that side must travel through more material (the target itself) before reaching the image receptor. As a result, the radiation that reaches the detector is less intense on the anode side, making the anode side less effective for imaging purposes.

Understanding the heel effect is crucial for positioning and technique in mammography. Technologists typically position the denser or more involved breast tissue toward the cathode side of the x-ray beam to take full advantage of the increased intensity there, allowing for better imaging of critical areas. This knowledge ensures that the images produced are of higher