Abstract: A gamma detection and modeling system in which the energy deposition and incident locations on two detectors are used to calculate the source. The detector assembly and processing means are provided as distinct units allowing the detectors' use in radioactive and other inaccessible areas. The gamma radiation image can be superimposed on an optical image of the monitored location. Various detector arrays from a simple pair of detectors through single first and multiple second detectors to combinations of such detector pairs are disclosed together with a method for their use.