What characterizes K-edge filters?

K-edge filters are characterized by their design, which utilizes layers specifically engineered to absorb different photon energies. This capability allows the filter to selectively absorb certain energies of X-ray photons based on the K-edge of elements incorporated in its structure.

The K-edge refers to the specific energy level at which an inner-shell electron of an atom is ejected, which directly relates to the absorption characteristics of that atom. By constructing filters from materials that have distinct K-edges, these filters can enhance contrast in imaging applications by allowing only certain energies to pass through, while effectively absorbing others.

This design principle is crucial for optimizing imaging techniques like mammography or dual-energy X-ray absorptiometry, where precise measurement of bone density or soft tissue contrast is required. The ability to absorb only specific photon energies while allowing others to pass is what defines the effectiveness of K-edge filters in medical imaging contexts.