Abstract: A method for dynamically determining the position and orientation of the bone elements of the spine of a person by internal imaging, includes: calculating in a first stage t, the relationships of the vertebrae to one another and relative to the surface of the back; determining equations for a dynamic mechanical model of the spine and for internal stresses on the spine and interactions between the spine and the surface of the back; producing in a second stage t+1, 3D images of the outer surface of the back of the person; and determining for stage t+1, the position and orientation of each of the vertebrae from data acquired from 3D images of the outer surface of the back during stage t+1 and from static position and orientation of data calculated for each of the vertebrae as well as for the shape of the surface of the back during stage t.

Abstract: A calibration system is disclosed for a stereoradiographic device having an X-ray source and a vertical X-ray receiver, the calibration system includes a horizontal table which rotates between two reference positions that are separated by 90 degrees in a horizontal plane of the table. A vertical frame is fastened to the horizontal table and is symmetrical with an axis of rotation of the table, the frame accommodates a patient that remains stationary relative to the frame as the table is rotated between its two reference positions wherein corresponding X-ray photographs are taken. At least three markers made of radio-opaque material are firmly attached to the frame, one of the markers represents the origin of orthogonal X,Y and Z axes, a second of the markers is located at a predetermined point along the X-Y axes, the third marker located at a known distance along the Z axis, the markers defining respective distances Lx, Ly or H relative to the origin.

Abstract: The invention relates to an RX stereoradiography device comprising a horizontal rotating plate (13) which is optionally translational, characterized in that said plate (13) can be oriented according to two angular positions at 90°, each of which in order to take two photos which are orthogonal in relation to the other, also characterized in that the device also comprises a frame (14) which is joined to the horizontal plate (13) and, optionally, an additional maintenance device (15) for receiving the subject and at least three markers (16) made of a radio-opaque material disposed in a connected manner on the frame (14), one of said markers (1) being identified as the origin of an orthogonal, three-dimensional point of reference and the other markers (16) being disposed in such a way that it is possible to provide, by projection, knowledge of at least one distance value between the markers (16) according to the three axes X, Y and Z of said point of reference, respectively Lx, Ly and H.