The invention relates to an image processing method for image processing, using a first CT image (PL-CT) of an object containing a target object, comprising pixels and pixel values associated therewith, and a second image (K-CT) of the object recorded at another time. The first CT image (PL-CT) and the second image (K-CT) are compared to each other in terms of the target object. Taking into account the comparison, a movement of the target object is carried out inside the first CT image (PL-CT), by reallocating pixel values to pixels. Said method is especially suitable for using in an irradiation planning system.
