The decay properties of 198Au have led to widespread interest in its potential use in radiotherapy for cancer treatments.

This isotope was conclusively identified in 1937 following neutron irradiation of stable 197Au and was ascribed a half-life of approximately 2.7 days.

[6] For this reason, 198Au nanoparticles are being investigated as an injectable treatment for prostate cancer.

This has been used extensively since artificial radioisotopes became available in the 1950s, as a supplement to millennia of investigations using other tracing techniques.

A jacket of natural 197Au (the only stable gold isotope), irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 198Au with a half-life of 2.697 days and produce approximately 0.411 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several days.