A method and apparatus for determining the three-dimensional movement of a patient positioned on a table between an X-ray source and an image receiver of an X-ray imaging apparatus. The apparatus has an X-ray source positioned opposite an image receiver, the X-ray source and the image receiver being driven in rotation about an axis. The method and apparatus has the following operation: at least three radio-opaque markers are placed on the patient's body; at least one first radiographic image of the patient is taken for a first determined fixed position of the imaging apparatus; at least one second radiographic image of the patient is taken for a second determined fixed position of the imaging apparatus; and a matrix of the three-dimensional movement of the patient with respect to the X-ray source of the imaging apparatus is determined on the basis of the two-dimensional movements of the markers in the radiographic images, the X-ray source constituting a fixed reference frame.