Where will the greatest dose savings be realized with increasing levels of beam filtration?

Increasing levels of beam filtration are most effective in reducing patient dose in the initial layers of tissue struck by the beam. The purpose of beam filtration is to absorb lower-energy photons from the x-ray beam, which are largely responsible for unnecessary radiation dose. These low-energy photons do not contribute significantly to image formation but can increase the likelihood of dose-related effects in the tissues they encounter.

When filtration is applied, these low-energy photons are absorbed before they reach the patient, resulting in a decrease in the number of photons interacting in the initial layers of tissue. This leads to a more efficient beam reaching the patient, as higher-energy photons, which have a better chance of penetrating deeper tissues and contributing to useful diagnostic information, are kept.

If filtration were to be effective throughout all layers evenly or primarily in the final layers, it would not optimize patient dose reduction since the most harmful and wasteful interactions are avoided by preventing those lower-energy photons from interacting with the initial layers of tissue in the first place. Hence, the most significant dose savings occur at the entry point where initial tissue absorption takes place.