C-arm systems and method for making and using continuous C-arm spin acquisition trajectories for dynamic imaging and improved image quality are described. In such systems and methods, a C-arm gantry, coupled to a C-arm support assembly, is adapted to retain an x-ray source and an x-ray detector. The C-arm gantry is selectively rotatable relative to the C-arm support assembly about both a C-arm axis and a pivot-axis to displace the x-ray source and the x-ray detector along a continuous C-arm spin trajectory. The C-arm system is adapted for continuous three-dimensional acquisition of data along the continuous C-arm spin trajectory including a plurality of shorts arcs and a plurality of long arcs. The C-arm system is adapted for continuous three-dimensional acquisition of data along the continuous C-arm spin trajectory to provide continuous three-dimensional imaging of dynamic processes.