In a method to control the acquisition and/or evaluation procedure of image data in medical examinations, in a previously acquired planning image data set entirely or partially covering a target volume, spatial information of the target volume is determined automatically using a statistical model of the target volume based on data about real anatomy. The acquisition and/or evaluation operation is controlled using the spatial information. A statistical model of at least one greyscale value distribution in the region of the surface of the target volume is used to calculate the location information.