Abstract: A method of calibration for reconstructing three-dimensional models from images obtained by a tomography apparatus comprising a radiation detector and an X-ray source which can move with respect to the detector. In the method a set of markers are placed in the field of the X-rays and the positions of the projections of the markers onto the images acquired are processed so as to deduce from this the position of the source at the time of acquisitions, the markers being carried by one and the same support. The markers are fixed with respect to the support and the positions of the projections of the markers onto the images acquired are processed so as to deduce from this the position of the markers in space.

Abstract: Method and apparatus and computer programs and computer medium for improving quality of a radiographic image of an object obtained by an X-ray apparatus containing an antidiffusion grid, placed between the object and a receiver of radiographic images, The grid is displaced in rectilinear translation in its plane on pickup of the image, between two positions according to a time displacement law which is a continuous curve with a time precision of approximately ±10% presenting at least five separate parts, the displacement taking place at constant speed over at least two parts and at variable speed over at least one part.

Abstract: A beam filtering device comprises a strip carrying at least one filter. The strip is wound onto drums between which the strip extends. A rotary drive mechanism drives the drums in rotation to cause the strip to advance and wind onto one drum while unwinding from the other. Advancing the strip makes it possible to arrange one of the filters on the strip in the space between the drums. This allows radiation filtering characteristics to be readily and rapidly modified.

Abstract: Method and apparatus for medical radiology and, in particular, galactography in the field of mammography. The method of obtaining radiological images in galactography comprises acquiring of a first radiological image of the breast in a compressed state: introducing a contrast medium in a part of the breast; acquiring at least a second radiological image of the breast in the compressed state and with contrast medium; and partial or complete subtraction of the first image in relation to the second image, or vice versa. An apparatus for use of the method comprises means for maintaining a breast compressed or immobilized and means for holding a catheter or the like for introducing a contrast medium in the breast.

Abstract: Method and system for compensating for the thickness of an organ in a radiology instrument, in which an image of the radiological thicknesses of the organ through which the X-ray beam has passed is calculated on the basis of a digitized image, the thickness image is filtered using a low-pass filter in order to obtain a low-frequency image, the low-frequency image is subtracted from the radiological thickness image in order to obtain a contrast image, the low-frequency image is processed using a pre-recorded table taking into account a contract &khgr; selected by a user in order to obtain an image with reduced dynamic range, and the image with reduced dynamic range is added to the contrast image in order to obtain a compensated thickness image, the pixels having a level below or above a predetermined threshold being returned at least to the value of the threshold, while preserving the differences and real ratios between the anatomical structures.

Abstract: Method and apparatus for examination of a breast, in which a contrast medium is injected in the breast to be examined, an X-ray beam is emitted in the direction of the breast; a plurality of digital images of the X-ray beam is taken after it has crossed the breast, and a representative image of the contrast produced in the tissues of the breast is calculated from the digital images.

Abstract: The movement of an anti-scatter grid in a radiography apparatus is a continuous curve having point symmetry with respect to the point whose time coordinate is equal to half the exposure time, and for which the space derivative of the time variable has two linear portions which are symmetrical with respect to a symmetry axis passing through the middle of the range of movement of the grid. The grid is moved with a high rate of movement close to the starting position and the end position.

Abstract: Method and system for compensating for the thickness of an organ in a radiology instrument, in which an image of the radiological thicknesses of the organ through which the X-ray beam has passed is calculated on the basis of a digitized image, the thickness image is filtered using a low-pass filter in order to obtain a low-frequency image, the low-frequency image is subtracted from the radiological thickness image in order to obtain a contrast image, the lowfrequency image is processed using a pre-recorded table taking into account a contract &khgr; selected by a user in order to obtain an image with reduced dynamic range, and the image with reduced dynamic range is added to the contrast image in order to obtain a compensated thickness image, the pixels having a level below or above a predetermined threshold being returned at least to the value of the said threshold, while preserving the differences and real ratios between the anatomical structures.