An imaging system can use high-energy electrons at a low dose level to generate 3D computed tomography images and/or 2D radiographic images of living tissue and other objects. In some embodiments, a nozzle directs a source of high-energy electrons to the imaging target, and a detector system detects physical quantities of electrons that interact with the imaging target. In some embodiments, a computer system can calculate estimated paths taken by individual electrons within the imaging target, determine interactions between voxels of a digitized image of the imaging target and individual electrons, and reconstruct a digitized image of the imaging target based at least in part on the determined interactions between individual electrons and voxels. The imaging target can include but is not limited to living tissue, humans, pediatric patients, small animals, and other objects, such as those used in industrial applications.
