Abstract: The present invention relates to a novel, non-rotating tomographic imaging system, including a multi-source x-ray imaging module which includes multiple x-ray sources within a vacuum manifold, each equipped with a non-thermionic cathode which can reduce image scan time (and hence, motion artifacts), or delivered radiation dose, through under-sampled acquisition sequences, and without adding additional sources. The non-thermionic nature of the cathode enables rapid on/off switching of x-rays without concern as to the thermal mass or the thermal time-constant of the cathode. The modules can be flexibly interconnected to each other to allow configuration as part of a distributed ring of sources, or in other x-ray imaging geometries. Modularity provides the present invention an advantage in making it easier to debug and repair a distributed-source imaging system, such as a computed tomographic (CT) system.