Abstract: In an illustrated embodiment a plurality of radiation sources are arranged to define a scanning path and the sources are successively actuated to produce successively operative beams each of duration sufficient to be recorded, for example by means of a conventional moving photographic cassette. For the case of a linear scan path, an elongated anode may have a succession of continuously energized cathodes, each cathode having an associated blocking screen and being momentarily actuated by removal of the blocking potential. The successive cathodes are actuated in synchronism with the movement of a film cassette, for example, in any suitable manner, or electronic image storage may be utilized in the form of a stationary array of photodetector elements and the required number of arrays of storage units, with electronic sequencing control.