Record of radiation from radioactive material in an object, made by placing the object in close proximity to a photographic emulsion.

a photographic picture showing the position of radioactive substances in tissues, obtained by coating a squash preparation or a section with a photographic emulsion in the dark, and subsequently developing the latent image produced by the decay radiations

An autoradiograph is an image produced on a x-ray film or nuclear emulsion by the pattern of decay emissions (e.g., beta particles or gamma rays) from a distribution of a radioactive substance. In biology, this technique may be used to determine the tissue localization of a radioactive substance, either introduced into a metabolic pathway, bound to a receptor or enzyme, or hybridized to a nucleic acid. The film or emulsion is apposed to the labeled tissue section to obtain the autoradiograph (also called an autoradiogram).