Perspectives on the evolution and future of X-ray computed tomography

Stationary X-ray computed tomography (CT) replaces mechanical gantry rotation with electronically addressable, distributed X-ray sources, offering a post-rotation paradigm that overcomes fundamental temporal and mechanical limitations of conventional CT. By eliminating rotation, stationary CT enables ultra-fast multi-angle acquisition but also introduces coupled challenges, including cross-scatter contamination, limited photon flux, and sparse angular sampling. This Perspective focuses on stationary CT as a system-level imaging framework and emphasizes that its practical realization depends on the coordinated development of stationary hardware, spectral imaging, and physics-informed reconstruction. Spectral detectors provide information-rich measurements under sparse-view conditions, while advanced reconstruction methods integrate physical modeling and prior constraints to recover images from incomplete and noisy data. Rather than independent advances, these elements must be jointly designed to balance spatial resolution, temporal resolution, dose efficiency, and quantitative accuracy. Together, these considerations outline a co-design pathway toward clinically viable stationary CT systems.