A focal infection is a localized infection that can potentially lead to the development of systemic infectious or non-infectious diseases once it spreads to other parts of the body through the bloodstream or lymphatic system.

Secondary or systemic infections due to dissemination throughout the body of microorganisms whose primary focus of infection lies in the periodontal tissues.

Unstable isotopes of indium that decay or disintegrate emitting radiation. In atoms with atomic weights 106-112, 113m, 114, and 116-124 are radioactive indium isotopes.