Abstract: The present invention relates to a system (10) and method for the volumetric and isotopic identification of the spatial distribution of ionizing radiation from point or extensive radioactive sources (3) in radioactive surroundings. More specifically, this system (10) comprises a gamma radiation detector (2) and an optical transducer (1) joined to each other and linked to a control unit to detect the absolute position of radioactive sources (3) relative to a visual reference located in the radioactive surroundings, and to determine the radioactive activity of the sources, that is to say it detects the isotope composition of the radioactive sources (3).