Dynamic X-ray tomography with multiple sources

A novel time-dependent tomographic imaging modality with multiple source-detector pairs in fixed positions is discussed. All detectors record simultaneously time-dependent radiographic data (“X-ray videos”) of a moving object, such as a beating heart. The dynamic two- or three-dimensional structure is reconstructed from projection data using a new computational method. Time is considered as an additional dimension in the problem, and a generalized level set method [Kolehmainen, Lassas, Siltanen, SIAM J Scientific Computation 30 (2008)] is applied in the space-time. In this approach, the X-ray attenuation coefficient is modeled by the continuous level set function itself (instead of a constant) inside the domain defined by the level set, and by zero outside. A numerical example with simulated data suggests that the method enforces suitable continuity both spatially and temporally. A drawback of the method is that it is not applicable to real-time imaging.