A method is for providing an annotated medical image data set for a patient's radiotherapy planning. In an embodiment, the method includes providing a planning image rule for the radiotherapy planning, including a scanning rule and a first reconstruction rule； retrieving an annotation rule from storage, containing annotation instructions and a second reconstruction rule, different from the first reconstruction rule； acquiring raw data of the patient in accordance with the scanning rule； reconstructing a first and second medical image data set in accordance with the first and second reconstruction rules using the raw data； annotating the second medical image data set in accordance with the annotation instructions, to determine annotated image information； combining the first medical image data set with the annotated image information, to produce the annotated medical image data set； and providing the annotated medical image data set for radiotherapy planning of the patient.
