What effect does added filtration have on the x-ray beam?

Added filtration in radiography refers to the placement of additional material, typically aluminum, in the path of the x-ray beam before it reaches the patient. This practice primarily serves to improve the quality of the x-ray beam while possibly reducing its overall quantity.

When added filtration is applied, it selectively removes lower-energy x-rays from the beam. These lower-energy x-rays contribute little to imaging but increase patient exposure to radiation. By eliminating these less penetrating x-rays, the remaining beam becomes more effective at penetrating tissue, leading to improved image quality. Higher-energy x-rays are more likely to provide a clearer and more diagnostic image because they can pass through body tissues more effectively.

As a result, the quantity—or overall intensity—of x-rays reaching the patient may decrease due to the removal of less useful lower-energy photons. However, the remaining x-rays are of higher quality, meaning they have better energy for producing diagnostic images. This is why the impact of added filtration is characterized by decreased quantity of the beam while simultaneously increasing its quality.