An operating method for a polyplanar imaging system for time-resolved imaging of an object is provided. First and second data records are recorded at a fan angle β from different angular positions by a first and second imaging planes arranged at an offset angle γ relative to each other and swiveled through an angle of at least φ=180°+β. A third data record is created by selecting projection images from the first data record beginning from a starting angle α and from the second data record so that the third data record covers an angular range of at least φ. Three-dimensional images are reconstructed based on the third data record. The starting angle α is varied for continuously creating the third data record until α has attained its final value. The contrast of projection images in the third data record or of three-dimensional images is evaluated.