beam hardening, the process of increasing the average energy level of an x-ray beam by filtering out the low-energy photons. For example, in dentistry, as the x-ray beam passes through a metallic object, such as fillings, implants, or facial jewelry, the phenomenon of beam hardening results in two types of artifact: distortion of metallic structures as a result of differential absorption, and creation of streaks and dark bands that obscure anatomic structures.
