What is the purpose of added filtration to the x-ray beam?

Added filtration is employed in x-ray systems primarily to enhance the quality of the x-ray beam by increasing the average energy of the photons within it. This is accomplished by selectively removing lower-energy photons that contribute minimally to diagnostic quality while increasing the proportion of higher-energy photons that are more capable of penetrating tissue effectively.

Lower-energy x-rays are often absorbed by the patient’s skin and do not contribute to the diagnostic image; instead, they only increase the patient's exposure to radiation. By using added filtration, which typically includes materials like aluminum, the beam can be shaped to exclude these less useful lower-energy x-rays, thus allowing only those that can penetrate tissues better and provide clearer images to pass through.

This not only improves the quality of the diagnostic information obtained but also serves to reduce unnecessary radiation dose to the patient, aligning with the principles of radiation protection that aim to minimize exposure while maintaining the necessary diagnostic capabilities.