Abstract: A data derandomizer for use in a scintillation imaging system. The imaging system produces data signals representing radiation events and presents them to a continuously operating video tape recorder for recording and subsequent playback to an imaging apparatus. The recorder can accept the data signals only in discrete time slots. The digital signals are produced in response to radiation events occurring randomly in time and therefore also occur at random time intervals. A data stacking circuit provides for receipt and simultaneous storage of several data signals between the detector and the recorder, the storage being in priority levels according to the order of occurrence of the data signals. Inventory control circuitry controls the stacking circuit to present the data signals to the recorder synchronously with the time slots, notwithstanding the random occurrence of the data signals.