Resumen
[0001] The invention relates to a device and method for generating tomograms. By means of the combination of the device and method, results equivalent to those obtained with traditional CAT systems can be obtained, using very few projections obtained in a limited angular range of movement of a source-detector assembly and/or elevated mechanical tolerance in the positioning of the source and detector. The device comprises: an X-ray imaging device with an assembly comprising an X-ray source (1) and an X-ray detector (2), with movement; a surface scanning device (4); and a data control and processing system configured to execute at least one calibration routine and one specific tomogram generation routine that uses data obtained by the X-ray imaging device and the surface scanning device to refine the geometric calibration according to the current trajectory and obtain a clinical-quality tomographic image (suitable for clinical diagnosis).
Reivindicaciones
1. Apparatus for generating tomographies comprising: - an X-ray imaging device that in turn comprises: - an X-ray source (1), - an X-ray detector (2), and the X-ray source (1) and the X-ray detector (2) are facing each other in order to receive between them a body (5) of which the tomography will be generated; and the X-ray source (1) and the X-ray detector (2) can have a joint movement or be moved independently, with the possibility of moving one of them or both with a predetermined trajectory following an isocentric or non-isocentric orbit (3); - a surface-scanning device (4) configured to obtain data from the surface of the body (5), - a data control and processing system configured to execute at least: - a routine for the geometric calibration of the apparatus that is applied periodically, and - a routine for generating tomographies that uses the projection data obtained with the X-ray imaging device (1, 2) combined with the data obtained with the surface-scanning device (4) and performs at least one of the following substages: - refinement of the geometric calibration of the apparatus using the projection data obtained with the X-ray imaging device (1, 2) combined with the data obtained with the surface-scanning device (4) that enables the correction of the geometric errors of the relative positions of the source and the detector at each projection position in the specific trajectory followed by the X-ray imaging device (1, 2) during the scanning of the body (5) due to the mechanical tolerances thereof; - generation of a tomographic image from the projection data obtained with the X-ray imaging device (1, 2) combined with the data obtained with the surface-scanning device (4) that enables the reconstruction of images of clinical quality from projection data obtained within an angular range less than the one defined for short scan and/or with an increased angular step (greater than one degree). 2. The apparatus for generating tomographies according to claim 1, characterized in that the surface-scanning device (4) is a contact scanning device. 3. The apparatus for generating tomographies according to claim 1, characterized in that the surface-scanning device (4) is a non-contact scanning device. 4. The apparatus for generating tomographies according to claim 1, characterized in that the surface-scanning device (4) is attached to a part of the X-ray imaging device (1, 2). 5. The apparatus for generating tomographies according to claim 1, characterized in that the surface-scanning device (4) is completely independent from the X-ray imaging device (1, 2), including the possibility of it being held and moved manually. 6. The apparatus for generating tomographies according to claim 1, characterized in that the surface-scanning device (4) is the X-ray imaging device (1, 2) itself. 7. A method for generating tomographies with the apparatus for generating tomographies of claims 1 to 6 comprising the stages of: a) periodically performing the geometric calibration of the equipment; b) obtaining projection images, with the X-ray imaging device; and is characterized in that it subsequently comprises the following stages: c) obtaining data from the surface of a body (5) with the surface-scanning device (4); d) executing the routine for generating tomographies that uses the projection images obtained with the X-ray imaging device (1, 2) combined with the data obtained with the surface-scanning device (4) and comprises at least the following stages: d1) generation of a 3D mask (5) of the body from the data obtained with the surface-scanning device (4); d2) preliminary reconstruction of the projection images obtained with the X-ray imaging device (1, 2) by using the geometric calibration periodically obtained in stage a); d3) 3D registration of the preliminary reconstruction obtained in substage d2) with the 3D mask of the body (5) obtained in substage d1) from the data obtained with the surface-scanning device (4); d4) refinement of the geometric calibration of the apparatus using the projection data obtained with the X-ray imaging device (1, 2) in stage b) combined with the 3D mask of the body (5) registered in substage d3) that enables the correction of the geometric errors of the relative positions of the source and the detector at each projection position along the specific trajectory followed by the X-ray imaging device (1, 2) during the scanning of the body (5) due to the mechanical tolerances thereof, d5) generation of a tomographic image from the projection data obtained with the X-ray imaging device (1, 2) in stage b) combined with the 3D mask of the body (5) registered in substage d3) that enables images of clinical quality to be reconstructed from data obtained within an angular range less than the one defined for short scan and/or with an increased angular step, greater than one degree. 8. The method for generating tomographies according to claim 7, characterized in that substage d4), refinement of the geometric calibration of the apparatus, comprises the following steps: i) simulating the projections of the 3D mask of the body registered in substep d3) by using the initial geometric calibration of the apparatus obtained periodically in stage a); and ii) performing a registration, projection by projection, of the simulated projections of the registered 3D mask obtained in step i), with the projection images obtained by the X-ray imaging device in stage b); iii) refining the geometric calibration of the apparatus periodically obtained in stage a) with the registration values obtained in step ii) in order to obtain a refined calibration file with the relative positions of the source and the detector for each projection position in the specific trajectory followed by the X-ray imaging device during the scanning of the body.
