The Gamma Locator DXI is a medical instrument locating enhanced gamma radiation emitted by radioactive tracers injected into patients. This allows determination of tracer concentrations, particularly in cancerous manifestations. Contrary to all other state-of-the-art devices of that kind, the Gamma Locator DXI does not use passive collimation of the gamma detector, but relies on a patented electronic collimation employing several detector elements and sophisticated analysis algorithms to distinguish the often abundant background radiation from the target gamma rays.