CT scanner and method for performing a CT examination of a subject - Patents.com

Abstract

To provide a CD scanner for performing CT scanning of a subject, and a method.SOLUTION: A CT scanner 1 includes a scanning conveyor 9 which is fitted onto a support structure and moves a subject for a CT inspection through a scanning area 8; an input conveyor 10 configured to convey the subject to a scanning chamber 2; and an output conveyor 11 configured to convey the subject outside the scanning chamber 2. The scanning conveyor 9 moves the subject mounted on support means 19 forward through the scanning area 8 and simultaneously rotates the support means 19 and the subject in the state that the support means 19 and the subject are in contact with each other. The input conveyor 10 and the output conveyor 11 are adapted to shielding bodies 16, 17, 18 configured to cut off all X-rays that are discharged by the scanning area 8 and to leave the scanning chamber 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a CT scanner and a method for performing a CT examination of an object, in particular to a CT scanner intended for use in the industrial sector, in particular in plants in continuous operation.

[0002] As an example, the present invention can be used to perform tomographic inspection of food products (fruit, bread, food packaged in jars and cans) to verify their internal quality or to check for the absence of undesirable contaminants (such as plastic or glass fragments), or to inspect 3D printed products (e.g., to check their internal composition that is otherwise inaccessible), etc.

[0003] Furthermore, it should be noted that in the context of this specification, a tomographic examination refers to the reconstruction of a three-dimensional model formed by a plurality of voxels and related to the density of the object. In particular, each voxel may be associated with both a value related to the absolute density of the object in its region and a value related to the density change in its region (such as a value indicating the density gradient). In the context of this specification and the appended claims, the definition of a three-dimensional model obtained by a tomographic examination also includes models with approximations that are greater or smaller than the actual numerical values. What is important is that the model is appropriate for the type of information to be obtained (for example, even a very approximate evaluation of local density variations may be sufficient to detect the presence or absence of solid foreign objects in a carton of yogurt).

[0004] Currently, tomography systems are mainly divided into rotor-based systems, which are commonly used both in medicine and industry (e.g., in the wood processing field), and rotating object-based systems, which are commonly used in laboratories.

[0005] In the former, the rotor is a mechanical structure on which both the X-ray source and detector are mounted, which moves completely around the scanned object, which either remains stationary or moves along one axis.

[0006] In the latter, both the x-ray source and the detector remain stationary, but the object must be moved in a precisely controlled manner within the irradiation field.

[0007] Rotor-based systems are expensive due to the need for sophisticated rotating equipment, and rotors tend to be large structures that cannot be easily placed around the area through which the scanned object passes as it moves continuously along a path.

[0008] On the other hand, known rotating subject-based systems require the scanned subject to be fixed to a system that rotates (and potentially moves) the subject in a precise and predetermined manner. Alternatively, therefore, the support for the subject may be mechanically connected to a support structure with either a single degree of freedom (rotation) or two degrees of freedom (such as to simultaneously rotate and advance in a controlled manner along a linear path).

[0009] One of the main problems of known CT scanners connected to a continuous system (the CT scanner cannot be completely closed during use) is the risk that X-rays may escape through the apertures necessary for the entry and exit of the object to be examined. The danger specifically concerns X-rays that may be generated by the physical phenomenon of scattering. This is a phenomenon in which each material that the X-rays strike absorbs part of the incoming radiation and at the same time emits additional radiation in all directions. This occurs when the first incoming radiation strikes the object. The same phenomenon is repeated when the radiation generated by scattering strikes another material in turn.

[0010] Relatively dense specimens require higher power x-rays emitted by the CT scanner, which results in higher power x-rays being generated by scattering.

[0011] In the case of a continuous CT scanner such as that described in this invention, the scattering phenomenon is particularly relevant in that the scanning chamber has an entrance opening and an exit opening to which a conveyor is connected (and which is open at the other end).

[0012] Although the conveyor is surrounded by X-ray shielding, if the conveyor were to run in a straight line there is a real risk that X-rays could escape unblocked from the CT scanner.

[0013] Similar problems exist with equipment used to perform simple radiological screening of subjects, such as airport security checks.

[0014] To attempt to overcome this shortcoming in certain types of equipment used to perform radiographic examination of subjects, solutions have been developed over the years in which the conveyor for the subject extends in a non-linear manner, for example by offsetting the position of the entrance and exit areas of the conveyor relative to the scanning area.

[0015] Although this manufacturing solution makes it possible to limit the risk of unwanted X-ray radiation, the non-linear inlet and outlet paths have so far only been usable for a limited number of specimens, i.e. those that are not at risk of being damaged by impact against the conveyor sidewall in the non-linear sections where the specimen regularly strikes the conveyor sidewall, whereas this manufacturing solution cannot be used for somewhat delicate products such as packed bread.

[0016] Several examples of CT scanners for transporting subjects, particularly for radiological examination devices, are described in the following patent documents: US Pat. Nos. 5,393,211, 5,393,325, 5,393,410, 5,393,625, 5,393,710, 5,393,625, and 6,493,345. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] British Patent No. 1156756 [Patent Document 2] European Patent Publication No. 0326471 [Patent Document 3] U.S. Patent No. 4,989,225 [Patent Document 4] U.S. Patent No. 5,119,408 [Patent Document 5] U.S. Patent No. 5,152,38099 [Patent Document 6] Patent No. 06133959 [Patent Document 7] Canadian Patent No. 2415409 [Patent Document 8] International Publication No. 9904481 [Patent Document 9] U.S. Patent No. 643710 [Patent Document 10] European Patent Publication No. 1283417 [Patent Document 11] International Publication No. 200439706 [Patent Document 12] International Publication No. 200696296 [Patent Document 13] International Publication No. 20078466 [Patent Document 14] International Publication No. 2009130645 [Patent Document 15] International Publication No. 201094774 [Patent Document 16] International Publication No. 201111196 [Patent Document 17] International Publication No. 201142750 [Patent Document 18] International Publication No. 201412861 [Patent Document 19] US Patent Application Publication No. 20140373792 [Patent Document 20] German Patent Application Publication No. 102015101378 [Patent Document 21] European Patent Publication No. 3106863 [Patent Document 22] German Patent Application Publication No. 102016107272 [Patent Document 23] International Publication No. 2019129561 [Non-patent literature]

[0018] [Non-Patent Document 1] Pack, Jed D., Frederic Noo, and H. Kudo. "Investigation of saddle trajectories for cardiac CT imaging in cone-beam geometry." Physics in Medicine & Biology 49.11 (2004): 2317 Summary of the Invention [Problem to be solved by the invention]

[0019] In this regard, it is a technical object of the present invention to implement a CT scanner that provides a solution to the above-mentioned problems.

[0020] In particular, the technical object of the present invention is to implement a CT scanner and method for performing CT scans of an object, which at the same time ensures a reduced risk of unwanted X-ray radiation, makes it possible to perform CT scans of any kind of object, and ensures a relatively high productivity and a high versatility. [Means for solving the problem]

[0021] The technical object and above intentions are substantially achieved by a CT scanner and a method for performing a CT scan of a subject according to the subject matter of the appended claims. [Brief description of the drawings]

[0022] Further features and advantages of the present invention will become more apparent by carefully reading the detailed description of several preferred, non-limiting embodiments of a CT scanner and a method for performing a CT scan of an object, as illustrated in the accompanying drawings. [Figure 1] 1 shows a schematic partial cross-sectional plan view of a CT scanner made in accordance with the present invention; [Diagram 2] 1 shows a schematic plan view of a scanning area of ​​a CT scanner according to a first embodiment of the present invention; [Diagram 3] FIG. 1 shows a schematic front view of a scanning area of ​​a CT scanner according to a first embodiment of the present invention; [Figure 4] FIG. 2 shows a schematic front view of a scanning area of ​​a CT scanner according to a second embodiment of the present invention; [Diagram 5] 4A-4D show schematic front views of one possible movement of a support unit in the scanning area of ​​a CT scanner according to a further embodiment of the present invention; [Figure 6] 4 shows a schematic plan view of a further variant of a scanning conveyor forming part of a CT scanner according to the invention; [Figure 7] 1 shows a schematic plan view of a module that can be used in a conveyor of a CT scanner according to a further variant of the invention; [Figure 8] FIG. 8 shows a schematic plan view of a conveyor comprising a number of modules of the type shown in FIG. 7; [Figure 9] 4 shows a schematic plan view of a conveyor according to a further embodiment of the present invention; [Figure 10] FIG. 10 shows a schematic plan view of a detail of the conveyor in FIG. [Figure 11] 1 shows a schematic front view of a further embodiment of a scanning conveyor usable in the present invention; [Figure 12] 12 shows a schematic plan view of the scanning conveyor of FIG. 11. [Figure 13] 1 shows a schematic plan view of a further embodiment of a scanning conveyor usable in the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] With reference to the above figures, a complete CT scanner according to the present invention is assigned the reference number 1.

[0024] Like known CT scanners, the one described in the present invention comprises a support structure (which may be either a single body or a number of distinct members) on which is mounted a scanning chamber 2. In use, a radiographic image of a subject 3 is captured, said radiographic image being usable in known manner for tomographic reconstruction.

[0025] The scanning chamber 2 is provided with an entrance opening 4 through which, in use, the subject 3 enters, and an exit opening 5 through which, in use, the subject 3 exits the scanning chamber 2 itself.

[0026] In some embodiments, the inlet opening 4 and the outlet opening 5 may also be coincident.

[0027] In some embodiments, the CT scanner is of the tunnel type.

[0028] At least one X-ray emitter 6 and one X-ray detector 7 (there can be more than one) are mounted inside the scanning chamber 2. The at least one X-ray emitter 6 and one X-ray detector 7 are stationary with respect to a support structure. The X-ray emitter 6 and the X-ray detector 7 are spaced apart opposite each other so as to define a scanning area 8 between the X-ray emitter 6 and the X-ray detector 7. Furthermore, the X-ray emitter 6 is configured to emit X-rays through the scanning area 8 towards the X-ray detector 7. In a known manner, then, the X-ray detector 7 is a two-dimensional sensor configured to capture data on the X-rays passing through the object 3, said data generally consisting of the residual intensity of the X-rays reaching each cell of the sensor. These data are usually stored as two-dimensional maps that can be presented as images (in practice, they are computed radiographic images).

[0029] According to the invention, a scanning conveyor 9 is mounted on a support structure and configured to move a subject 3 for CT examination through the scanning region 8 by moving the subject 3 forward from the entrance opening 4 to the exit opening 5.

[0030] For the supply and removal of the objects 3 to the scanning chamber 2, the CT scanner 1 further comprises an input conveyor 10 and an output conveyor 11. The input conveyor 10 is mounted on a support structure and configured to guide the objects 3 along an input path 13 by transporting them from an input area 12 of the CT scanner 1 to an entrance opening 4 of the scanning chamber 2, while the output conveyor 11 is configured to guide the objects 3 along an output path 15 by transporting them from an exit opening 5 of the scanning chamber 2 to an output area 14 of the CT scanner 1. Depending on the embodiment, the input conveyor 10, the scanning conveyor 9 and the output conveyor 11 may be different devices or may be composed of consecutive parts of a single device, as illustrated in FIG. 1. Furthermore, in some embodiments, all or part of the input conveyor 10 and the output conveyor 11 may be composed by a single device.

[0031] In some embodiments, the input area 12 and the output area 14 may be coincident.

[0032] In order to minimize the risk of unwanted escape of X-rays from the scanning chamber 2 into the environment surrounding the CT scanner, the latter comprises at least a first shield 16, a second shield 17 and a third shield 18. The first shield 16, the second shield 17 and the third shield 18 are configured to shield X-rays. In a known manner, the first shield 16, the second shield 17 and the third shield 18 may each be composed of a number of shields advantageously connected. Depending on the embodiment, the first shield 16, the second shield 17 and the third shield 18 may be separate (as illustrated in FIG. 1) or may be totally or partially integrated.

[0033] The first shield 16 at least partially surrounds the input conveyor 10, the second shield 17 at least partially surrounds the output conveyor 11, and the third shield 18 surrounds the scanning chamber 2. If the input conveyor 10 and the output conveyor 11 are entirely or partially configured in one device, the first shield 16 and the second shield 17 are entirely or partially coincident.

[0034] According to a further aspect of the invention, the input conveyor 10, the scanning conveyor 9 and the output conveyor 11 are advantageously configured to move forward a subject 3 mounted on a support means 19. The subject 3 is mechanically removed from the support means 19 (i.e. can be freely placed on and removed from the conveyors). In at least some embodiments, the CT scanner 1 comprises a plurality of support units 19 (the plurality of support units 19 may be provided separately from the CT scanner 1).

[0035] In a preferred embodiment, in particular, the support means 19 may advantageously be shaped like a tray or sled and defines an upper stationary surface 20 constituting the surface on which the specimen 3 is placed.

[0036] As will be better explained below, in the two preferred embodiments identified so far by the applicant, the support means 19 is mounted above the input conveyor 10, the scanning conveyor 9 and the output conveyor 11 either by simply resting them on top of each other (Figure 3) or by magnetic levitation (Figures 4 and 5 - a particularly preferred construction solution at the moment which ensures the best possibility of controlling the movement of the support means 19).

[0037] Furthermore, the scanning conveyor 9 is configured to move the object 3 placed on the support means 19 forward through the scanning area 8 and simultaneously rotate at least a part of the support means 19 and the object 3 in contact with each other so as to gradually orient the object 3 in a number of different angular positions relative to the X-ray emitter 6 and the detector 7 (FIG. 2). Advantageously, the scanning conveyor 9 is configured to move at least a part of the support means 19 and the object 3 in contact with each other and also rotate them relative to the scanning conveyor 9. In some embodiments, the scanning conveyor 9 is configured to move the object 3 placed on the support means 19 forward through the scanning area 8 and simultaneously rotate the entire support means 19 and the object 3 in contact with each other. In other embodiments, on the other hand, the scanning conveyor 9 is configured to simultaneously rotate only the object 3 and the part of the support means 19 on which the object 3 is placed, in contact with each other. In what follows, reference will be made to the rotation of the subject 3 and the support means 19 themselves and, unless the context indicates otherwise, to both rotating the entire support means 19 and rotating only the part of the support means on which the subject rests.

[0038] As the subject 3 moves forward through the scanning region 8 and the subject 3 itself rotates, the X-ray detector 7 can capture data regarding the X-rays passing through the subject 3 multiple times, with each capture having the subject 3 having a different orientation relative to the X-rays passing through the subject 3, as occurs in any CT scanner.

[0039] In accordance with a further aspect of the present invention, the input conveyor 10 and first shielding 16 are configured such that the first shielding 16 blocks any x-rays (i.e., directly emitted x-rays without considering subsequent diffusion that would change the line of propagation) that emanate from the scanning region 8 and exit the scanning chamber 2 through the entrance opening 4. In particular, the input conveyor 10 and first shielding 16 are configured such that these x-rays cannot freely reach the input region 12. It should be noted that in the context of this specification and the appended claims, the intention of the shielding blocking certain x-rays is merely to provide a geometrical implication that these x-rays propagate in a straight line that must intersect the shielding, and is not to suggest that the shielding actually absorbs the x-rays.

[0040] The output conveyor 11 and the second shield 17 are then configured such that the second shield 17 blocks any X-rays emerging (directly) from the scanning region 8 exiting the scanning chamber 2 through the exit opening 5. In particular they are configured such that these X-rays cannot freely reach the output region 14.

[0041] Although the preferred embodiment does not always envisage complete blocking of both the X-rays exiting from the entrance opening 4 and the X-rays exiting from the exit opening 5, it is also possible that one of the two conveyor shielding pairs is not configured according to the above if the CT scanner 1 is located somewhere where leakage of radiation from one of the two openings is not an issue for operator safety (this may be the case, for example, if the conveyor and its associated shielding are located inside a structure which itself serves as additional shielding).

[0042] According to a preferred embodiment, the input conveyor 10 and the output conveyor 11 define an input path 13 and an output path 15, respectively, which may be flat, serpentine, i.e., any non-linear path as shown in FIG. 1, or U-shaped, S-shaped, L-shaped, N-shaped, etc.

[0043] In many CT scanner 1 installations, in the context of a continuous system, the input area 12, the scanning area 8, and the output area 14 may have to be aligned in a straight line (as illustrated in FIG. 1). In this case, the first shield 16 preferably comprises a first shielding portion 21, and the input conveyor 10 (i.e., the input path 13) and the first shield 16 are configured such that the first shielding portion 21 is interposed between the input area 12 and the entrance opening 4. As a result, the first shield 21 can block any X-rays (typically due to diffraction-scattering-first order phenomena) emitted by the scanning area 8, exiting the scanning chamber 2 through the entrance opening 4, and directed towards the input area 12. Similarly, the second shielding 17 preferably comprises a second shielding portion 23, and the output conveyor 11 (i.e., the output path 15) and the second shielding 17 are configured such that the second shielding 23 is interposed between the output region 5 and the exit opening 14, such that the second shielding 17 is able to block any X-rays emitted by the scanning region 8, exit the scanning chamber 2 through the exit opening 5 and directed towards the output region 14.

[0044] To achieve this result, the input path 13 and the output path 15 may extend in a different direction through at least a portion of the first shielding portion 21 of the first shielding body 16 and through at least a portion of the second shielding portion 23 of the second shielding body 17, respectively.

[0045] In the embodiment shown in Figure 1, the first shielding portion 21 and the second shielding portion 23 are simply constituted by portions of respective shields that form relative paths having a convex pattern when viewed from the inside of the respective conveyors (i.e. so as to completely block the line of sight between the inlet / outlet opening 4 and the input / output area 12 / 14, respectively).

[0046] In a preferred embodiment, the scanning conveyor 9 is configured to rotate the support means 19 and the specimen 3 placed thereon about an axis of rotation transverse to, and preferably perpendicular to, the running surface 24 of the support means 19 (the running surface 24 is generally horizontal and generally defined by the scanning conveyor 9).

[0047] As mentioned above, in a preferred embodiment, at least one of the input conveyor 10, the output conveyor 11 and / or the scanning conveyor 9 (but preferably all) comprises a magnetic levitation conveyor and the support means 19 comprises a carriage which can be driven by magnetic levitation.

[0048] In this case, the interaction of the magnetic levitation conveyor with the carrier is intended, on the one hand, to keep the carrier elevated relative to the conveyor (FIGS. 4 and 5) and, on the other hand, to move the carrier relative to the conveyor, both with regard to its movement through the scanning area 8 and with regard to the rotation of the carrier itself (as shown diagrammatically in FIG. 2). The scanning conveyor 9 is thus a planar motor conveyor. As an example, one can use that currently marketed under the brand name Xplanar™ by the German company Beckhoff.

[0049] When a magnetic levitation conveyor is used, it is advantageous that the movement of both the support means 19 and the specimen 3, and the rotation of the support means 19 and the specimen 3 in contact with each other, occur solely by the magnetic levitation conveyor, without any physical contact between the magnetic levitation conveyor and the support means 19.

[0050] The use of magnetic levitation conveyors and special carriages is particularly preferred because, if properly designed, the carriage movements can be controlled with extremely high precision, which is compatible with performing accurate tomographic reconstructions.

[0051] When a magnetic levitation conveyor is used, the support means 19 can also be moved forward by the scanning conveyor through the scanning area 8 while modifying the inclination of the mounting surface for the subject 3 relative to the rotation axis (vertical in FIG. 5) about which the subject is rotated, in order to improve the subsequent tomographic image reconstruction, as shown in FIG. 5. Therefore, the rotational movement made by the subject 3 in the scanning area 8 does not have a fixed rotation axis.

[0052] Indeed, it is known that cone-beam tomography, in which rotation is performed around a single axis, does not allow accurate reconstruction of the entire volume, but instead is possible if, for example, a "saddle" trajectory is used (see, for example, "Patent Document 1"), or in any case if the subject is rotated around a generally arbitrary axis of rotation.

[0053] On the other hand, in other embodiments, at least one of the input conveyor 10, the output conveyor 11 and / or the scanning conveyor 9 may be configured with a started wheel conveying plane 25, or as far as the scanning conveyor 9 is concerned, with a started roller conveyor belt 26 of the two, the wheel conveying plane 25 being the preferred solution.

[0054] An example of a settling wheel conveying plane 25 is shown in FIG. 8 and is made up of a number of modules 27 (a single module 27 is shown in FIG. 7) with a substantially hexagonal plane. Each of the modules 27 has three settling wheels 28 (FIG. 7) rotatably mounted according to a coplanar rotation axis 22 (parallel to the running plane 24). The planar rotation axes 22 intersect each other in the center of the module 27 and are inclined to each other at an angle of 120°. Each settling wheel 28 can be operated independently of the others and can partially protrude from the top surface 29 of the module to serve as a platform for the support means 19. The modules 27 are mounted side by side as shown in FIG. 8 and together with the coplanar top surface 29 define the conveying plane 25. By separately controlling the rotation of each settling wheel 28, each support means 19 resting on the conveying plane 25 can be made to perform any movement in the running plane 24. One device of this type is, for example, promoted by Bremer Institut fur Produktion und Logistik GmbH under the brand Celluveyor.

[0055] On the other hand, an example of an activated roller conveyor belt 26 is shown in FIG. 9. This is the belt 26. In the belt 26, a two-dimensional cell matrix 30 is obtained (as shown enlarged in FIG. 10), on each of whose cells an activated roller 31 is mounted, respectively, whose axis 33 is inclined both to the line of travel of the belt 26 and to a line perpendicular to said line of travel. Each activated roller 31 rotates about an axis that is in the same plane as the belt 26 and is sized so that it protrudes both above and below the belt 26. By acting on the underside of the belt 26, the rotation of each individual activated roller 31 can be controlled to move the support means 19 resting on the belt 26 as required. Depending on the embodiment, all activated rollers 31 can have their axes of rotation parallel to each other, or groups of activated rollers 31 can have their axes of rotation inclined differently. An example of this type of conveyor is the one sold under the name Activated Roller Belt by Intralox, LLC in the USA.

[0056] 6 shows a different embodiment in which the scanning conveyor 9 consists of several conveyor belts 32 arranged side by side. These conveyor belts 32 can be controlled separately both with respect to their running line and their running speed. By appropriately combining the running line and running speed of each conveyor belt 32, both the running of the support means 19 placed on two or more of them and the rotation thereof can be controlled as desired.

[0057] In some embodiments, as already mentioned, only a part of the support means 19 rotates together with the object 3 while the object 3 is on the scanning conveyor. In these embodiments, the support means advantageously comprises a lower base 34 and a platform 35 rotatably connected to and arranged on said lower base 34 and configured to support the object 3.

[0058] In these embodiments, the scanning conveyor 9 comprises a mounting 36 configured to interact with a platform 35 of the support means 19. The mounting 36 is configured to contact the platform 35 or another element connected thereto, thus causing relative rotation of the platform 35 and thus the subject 3 with respect to the lower base 34.

[0059] 11 to 13 show two embodiments in which the scanning conveyor 9 is magnetically levitated, but similar solutions can be adopted for the other types of conveyors described.

[0060] In the embodiment of Figures 11-13, the lower base 34 is a magnetic levitation driven carriage and the upper platform 35 is associated with a toothed wheel 37 that protrudes sufficiently to be able to engage with a rack 38 that is part of the joint. More generally, the platform 35 may have a mating wheel that rolls on the joint 36 during rotation of the platform 35, causing the platform 35 to rotate. In fact, the toothed wheel 37 also rolls on the rack 38 as the two intermesh with each other and the base 34 slides relative to the joint 36 parallel to the direction of deployment of the rack 38.

[0061] Advantageously, the platform 35 is rotated by movement of the support unit 19 relative to the joint 36 .

[0062] In some embodiments, the joint 36 is fixed relative to the scanning conveyor 9 (eg, integral therewith, as shown in Figures 11 and 12).

[0063] In other embodiments, the joint 36 may be movable relative to the scanning conveyor 9. The mobility of the joint can be utilized both to rotate the platform 35 (passing close to the joint at a relatively high speed) while the base 34 is stationary or decelerated, and to optimally position the joint 36 relative to the trajectory of the base 34.

[0064] In the embodiment of FIG. 13, the mobile joint 36 also includes a magnetic levitation drive carriage.

[0065] To operate each active part of the CT scanner, there is an electronic operation control unit (not shown) operatively connected to each active part such as the emitter 6, the detector 7, the input conveyor 10, the output conveyor 11, the scanning conveyor 9, etc.

[0066] To enable a proper tomographic reconstruction of the object 3 under examination based on the data captured by the X-ray detector 7, the position of the object 3 relative to the emitter 6 and / or detector 7 must be known accurately. Depending on the embodiment, this result can be achieved by ascertaining the position of the object 3 precisely as it traverses the scan area 8 (e.g. by using a scanning conveyor 9 accordingly) or by gradually determining the position.

[0067] In this latter case, the CT scanner 1 further comprises a device (not shown) for detecting the position of the subject 3. This device for detecting the position of the subject 3 is associated with the scanning region 8 to determine the position of the subject 3 relative to the emitters 6 and / or the detector 7 when each acquisition is made by the detector 7.

[0068] Various examples of devices for detecting the position of the object 3 are described in more detail in patent application No. 102019000019454 in the name of the same applicant, to which reference is made.

[0069] Depending on the embodiment, the device for detecting the position of the subject 3 may be an autonomous device capable of providing information regarding the position of the subject 3 to the electronic operating and control unit or may consist of the electronic operating and control unit itself. Furthermore, the device for detecting the position of the subject 3 may operate simultaneously as each detection is made by the X-ray detector 7 by substantially real-time data processing or alternatively may operate at a later stage by processing previously acquired data.

[0070] In a preferred embodiment, the device for detecting the position of the subject 3 comprises a camera observing the scanning area 8. The relative position of the subject 3 within the scanning area 8 is then determined by a comparison between the images detected by the camera each time the X-ray detector 7 captures a calculated radiographic image. This comparison can be made by observing the movement of any of the characteristic points of the subject 3 and / or the support means 19, or by observing the movement of an identifier specifically given to the subject 3 or to the support.

[0071] The operation of the various variants of CT scanner 1 described above corresponds to specific embodiments of a more general method for performing a CT scan of a subject 3. It should therefore be understood that all components described above with respect to the CT scanner may also refer to this method and vice versa.

[0072] In this method, the scanned object 3 is placed on a mechanically free support means 19, and the support means 19 and the object 3 are moved forward into the scanning region 8. The step of moving the support means 19 and the object 3 forward into the scanning region 8 is performed by moving the support means 19 forward along a serpentine input path 13 that extends inside a first shielding 16 configured to block X-rays, such that all X-rays emitted by the scanning region 8 and entering the input path 13 are blocked by the first shielding 16.

[0073] The method then involves moving the support means 19 and subject 3 forward through the scanning region 8 while rotating the support means 19 and subject 3 in contact with each other. As the subject 3 moves and rotates through the scanning region 8, the method involves capturing multiple radiographic images of the subject 3 from different relative angles using x-ray emitters 6 and fixed x-ray detectors 7 mounted opposite each other on two opposing sides of the scanning region 8.

[0074] Once the radiological images have been captured, in the method they are combined to calculate a tomographic reconstruction of the object 3 .

[0075] Furthermore, when the object 3 leaves the scanning region 8, the method includes removing the support means 19 and the object 3 from the scanning region 8. Advantageously, the removing step is performed by moving the support means 19 forward along the serpentine output path 15 that runs inside the second shielding 17 configured to block X-rays, such that all X-rays emitted by the scanning region 8 and entering the output path 15 are blocked by the second shielding 17.

[0076] The invention offers significant advantages: indeed, it makes it possible to implement a CT scanner 1, which at the same time ensures a reduced risk of unwanted X-ray radiation, makes it possible to carry out CT scans of any kind of subject 3, ensuring a relatively high productivity and a high versatility.

[0077] Finally, it is worth noting that the present invention is relatively easy to manufacture and the costs associated with its implementation are not too high.

[0078] Many modifications and variations can be made to the present invention as designed herein without departing from the scope of the invention.

[0079] All details may be replaced by other technically equivalent details and any materials, shapes and dimensions of the various components may be used as required.

Claims

1. 1. A CT scanner comprising: A support structure; a scanning chamber mounted on the support structure and having an entrance opening and an exit opening; an x-ray emitter and an x-ray detector mounted in spaced opposed relation to each other within the scan chamber and stationary relative to the support structure; a scanning conveyor mounted on the support structure and configured to move a subject for CT examination from the entrance opening to the exit opening through a scanning region; an input conveyor mounted on the support structure and configured to transport the subject along an input path from an input region of the CT scanner to the entrance opening of the scanning chamber; an output conveyor mounted on the support structure and configured to transport the subject from the exit opening of the scanning chamber along an output path to an output area of ​​the CT scanner; a first shield configured to shield from X-rays and at least partially surrounding the input conveyor; a second shield configured to shield from X-rays and at least partially surrounding the output conveyor; a third shield configured to shield from x-rays and at least partially enclosing the scan chamber; Equipped with the x-ray emitter is configured to emit x-rays through the scanning region toward the x-ray detector; the input conveyor and the output conveyor are configured to move forward the object mounted on a support means that is mechanically removable from the object; the scanning conveyor is configured to move the object placed on the support means forward through the scanning region and to simultaneously rotate the support means and the object while at least a portion of the support means and the object are in contact with each other; the scanning conveyor is selected from actuated wheel conveying surfaces, actuated roller conveying belts, planar motorized conveyors, magnetic levitation conveyors, and conveyors consisting of a plurality of conveyor belts arranged side by side, each of which is independently controllable in both line of travel and speed of travel; When the scanning conveyor is a magnetic levitation conveyor, the support means is a magnetic levitation carriage. CT scanner.

2. 2. A CT scanner according to claim 1, the input conveyor and the first shield are configured such that the first shield blocks all x-rays emanating from the scan region and exiting the scan chamber through the entrance opening; the output conveyor and the second shield are configured such that the second shield blocks all x-rays emanating from the scan region and exiting the scan chamber through the exit opening. CT scanner.

3. 3. A CT scanner according to claim 1 or 2, wherein the input conveyor defines a serpentine input path.

4. 4. The CT scanner according to claim 3, wherein the input path extends while changing direction at least in a part of the first blocking portion of the first shielding body.

5. 5. A CT scanner according to any preceding claim, wherein the output conveyor defines a serpentine output path.

6. 6. The CT scanner according to claim 5, wherein the output path extends while changing direction at least in a part of the second blocking portion of the second shielding body.

7. 7. A CT scanner according to claim 1, wherein the scanning conveyor is configured to rotate at least a part of the support means and the subject placed on the support means about a rotation axis that intersects with a running surface on which the support means runs.

8. A CT scanner according to any one of claims 1 to 7, the input conveyor and / or the output conveyor are magnetic levitation conveyors; the support means being a magnetic levitation carrier; CT scanner.

9. 8. A CT scanner according to any one of the preceding claims, wherein the input conveyor and / or the output conveyor are comprised of a actuated wheel conveyor surface or an actuated roller conveyor belt.

10. A CT scanner according to any one of claims 1 to 9, The scanning conveyor is a magnetic levitation conveyor; The rotation of the support means and the subject is caused only by the magnetic levitation conveyor without any physical contact between the magnetic levitation conveyor and the support means. CT scanner.

11. A CT scanner according to any one of claims 1 to 9, the support means comprises a lower base and an upper platform rotatably connected to the lower base and configured to support the subject; the scanning conveyor including a joint configured to interact with the platform of the support means to rotate the platform and the subject relative to the lower base. CT scanner.

12. 12. The CT scanner of claim 11, wherein the platform comprises a coupling wheel that rotates on the joint during rotation of the platform to rotate the platform.

13. 13. A CT scanner according to claim 11 or 12, the joint is fixed or movable relative to the scanning conveyor; the platform is rotated by movement of the support means relative to the joint; CT scanner.

14. A CT scanner according to any one of claims 1 to 13, the scanning conveyor is a magnetic levitation conveyor; A CT scanner, wherein the scanning conveyor is programmed to modify the inclination of the scanning conveyor relative to an axis of rotation about which the scanning conveyor rotates such that a rotational motion performed by the subject within the scanning region has an indefinite axis of rotation by moving the scanning conveyor forward through the scanning region.

15. A CT scanner according to any preceding claim, further comprising an electronic operating and control unit.

16. 16. A CT scanner according to any one of claims 1 to 15, further comprising a device for detecting the position of the subject relative to the X-ray emitter and / or the X-ray detector at each capture by the X-ray detector.

17. 17. A CT scanner according to claim 1, wherein as the subject moves forward through the scanning region and rotates about itself, the X-ray detector captures data relating to X-rays passing through the subject multiple times.

18. 18. A CT scanner according to any one of claims 1 to 17, wherein the scanning conveyor is configured to rotate the support means and at least a portion of the subject with the support means and the subject in contact with each other, thereby rotating the support means and the subject relative to the scanning conveyor.

19. A CT scanner according to any one of claims 1 to 18, the inlet opening and the outlet opening are coincident; and / or the input domain and the output domain are coincident; and / or the input conveyor and the output conveyor are formed in whole or in part by the same device; The first shield and the second shield are entirely or partially identical to each other.

20. 1. A method of performing a CT examination of a subject, comprising: providing said subject on a mechanically released support means; providing said support means together with said subject to said scanning region; moving the support means together with the subject forward through the scanning region and rotating the support means and the subject in contact with each other; capturing a plurality of radiographic images of the subject from different relative angles using x-ray emitters and fixed x-ray detectors mounted opposite one another on two opposing sides of the scan region as the subject moves and rotates within the scan region; calculating a tomographic reconstruction of the subject by combining a plurality of the acquired radiographic images; removing the support means and the subject from the scanning region; having the step of feeding the support means together with the subject into the scanning region is performed by moving the support means forward along a serpentine input path extending inside a first shield configured to block x-rays such that all x-rays emitted by the scanning region and entering the input path are blocked by the first shield; removing the support means and the subject from the scanning region is performed by moving the support means forward along a serpentine output path that extends inside a second shield configured to block x-rays such that all x-rays emitted by the scanning region and entering the output path are blocked by the second shield; the step of moving the support means with the object forward through the scanning region is performed by a scanning conveyor selected from an actuated wheel conveying surface, an actuated roller conveying belt, a planar motorized conveyor, a magnetic levitation conveyor, and a conveyor consisting of a plurality of conveyor belts arranged side by side, the conveyor belts being separately controllable in both line of travel and speed of travel; When the scanning conveyor is a magnetic levitation conveyor, the support means is a magnetic levitation carriage. method.

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