Where is the x-ray beam intensity greatest due to the anode heel effect?

The x-ray beam intensity is greatest at the cathode end due to the anode heel effect, which stems from the geometry of the x-ray tube. In an x-ray tube, the cathode side is where the electrons are emitted and accelerated towards the anode. As these electrons strike the anode, they produce x-rays, but due to the angle of the anode, some of the x-rays generated are absorbed by the anode material itself.

This absorption is more pronounced towards the anode end, resulting in a decrease in x-ray intensity in that area. Conversely, the cathode side of the x-ray tube has a higher concentration of x-rays because fewer rays are absorbed before they exit the tube. Hence, the resultant beam is stronger on the cathode side, making it the area of highest intensity.

Understanding the anode heel effect is crucial for optimizing image quality in radiographic procedures, as it informs the positioning of patients and the selection of techniques to ensure that the most intense portion of the beam is directed toward the area of interest.