The invention relates to a data processing method of determining a change of an image of an anatomical body part of a patient's body, the method being executed by a computer and comprising the following steps: a) acquiring static medical image data comprising static medical image information describing anatomical body part in a first anatomical spatial state of an anatomical vital spatial change of the anatomical body part; b) acquiring patient model data comprising patient model information describing a model body part corresponding to the anatomical body part, wherein the patient model information describes the model body part in a plurality of model spatial states of a model vital spatial change corresponding to the anatomical vital spatial change; c) determining spatial state mapping data comprising spatial state mapping information describing at least one of a first mapping from the model body part in a first one of the plurality of model spatial states to the model body part in a second, different one of the plurality of model spatial states, the first model spatial state corresponding to the first anatomical spatial state, and a second mapping from the model body part in the first model spatial state to the anatomical body part in the first anatomical spatial state; d) determining, based on the static medical image data and the spatial state mapping data, transformed medical image data comprising transformed medical image information describing the anatomical body part in a second anatomical spatial state of the anatomical vital spatial change, the second anatomical spatial state corresponding to the second model spatial state.