An apparatus includes: an input configured to receive a plurality of images, wherein the images include respective sub-images of a bodily part of a subject, and wherein a position of the bodily part relates to a breathing movement and a cardiac movement of the subject a first registration engine configured to determine a first registration of at least two breathing correlated images, wherein the at least two breathing correlated images comprise two of the plurality of images or are derived from at least some of the plurality of images a second registration engine configured to determine a second registration of at least two cardiac correlated images and a volumetric image generator configured to generate a volumetric image using the first registration and the second registration.
