What is the primary purpose of composite filters?

Composite filters are designed to modify the x-ray beam by selectively removing certain components. The primary purpose of these filters is to eliminate unwanted characteristic x-rays, which are produced at specific energies that may not contribute to the diagnostic quality of the image. By removing these low-energy photons, the overall quality of the x-ray beam can be improved, resulting in enhanced image contrast and reduced patient dose, as these low-energy photons contribute to radiation exposure without adding diagnostic value.

The choice regarding increasing the energy of x-rays does not apply, as composite filters are focused on filtration rather than energy enhancement. The option about combining multiple materials for enhanced absorption touches on a relevant subject but does not capture the core function of these filters. Also, while decreasing overall radiation output can be a secondary effect of filtration, it is not the primary purpose, which is to improve the beam's quality, particularly by removing lower-energy x-rays.