Advertising in video games consider such advertisements to make up a category of their own. In-game advertising is similar to subtle advertising in films, where the advertising content is within the "world" of the movie. Thus billboards, storefronts, posters, apparel, vehicles, weapons, fliers, sponsored product placement, and the interplay between the player and these elements in the game allow for a great degree of virtual advertisement. Examples include billboards advertising for (and product placement of) Bawls energy drink in "", and billboards for Adidas sportswear in "FIFA International Soccer". The principal advantage of product placement in in-games advertising is visibility and notoriety. For advertisers
Commonly used gamma-emitting isotopes into a tumor such as a breast tumor, and the tumor is irradiated by gamma ray photons from the wire. At the end of the treatment the wire is removed. A rare but notable gamma source is sodium-24, this has a very short half-life but it emits photons with very high energies (>2 MeV). It could be used for radiography of thick steel objects if the radiography occurred close to the point of production. In common with Co-60 and Ir-192 it is formed by the neutron activation of the commonly found stable isotope. Americium-241 has been used as a source