In mammography, what effect does orienting the anode toward the chest wall in a cranial caudal view have on radiation exposure?

In mammography, orienting the anode toward the chest wall in a cranial-caudal view leads to a phenomenon known as the anode heel effect. This effect indicates that radiation exposure is not uniform across the x-ray beam; rather, it varies depending on the angle of the anode. When the anode is directed toward the chest wall, the x-ray beam's intensity is greater at the cathode side and decreases towards the anode side. Consequently, the area near the nipple, which is farther from the anode and closer to the cathode, receives a higher dose of radiation compared to the area near the chest wall.

This distribution means that in this positioning, the nipple, being situated further away from the anode, will have a greater exposure compared to that of the chest wall, where the x-rays have passed through a greater amount of material and scattered more. Therefore, radiation exposure indeed is greater at the nipple than at the chest wall in this specific orientation. Understanding this principle is essential for optimizing imaging techniques and minimizing radiation exposure to sensitive tissues during mammography.