In dynamic computed tomography a contrast agent is injected into a patient, and a region of interest where the contrast agent is flowing is then scanned with a computed tomography machine having a ray source and a ray detector. The ray source rotates. At a first rotational position of the ray source for a first rotation at a first time point a first image is obtained, and at the first rotational position for at least another rotation at a second time point a second image is obtained. For at least another rotational position of the ray source for the first rotation at a third time point a third image is obtained, and at the another rotational position for the another rotation at a fourth time point a fourth image is obtained. Time interpolations are performed and a reconstructed image is created.