(19)
(11)EP 2 960 686 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
29.05.2019 Bulletin 2019/22

(21)Application number: 15173496.9

(22)Date of filing:  24.06.2015
(51)Int. Cl.: 
G01V 5/00  (2006.01)

(54)

DETECTOR DEVICE, DUAL ENERGY CT SYSTEM AND DETECTION METHOD USING THE SYSTEM

DETEKTORVORRICHTUNG, CT-SYSTEM MIT DUALER ENERGIE UND ERKENNUNGSVERFAHREN MIT DEM SYSTEM

DISPOSITIF DE DÉTECTION, SYSTÈME DE TOMODENSITOMÉTRIE BIÉNERGÉTIQUE ET PROCÉDÉ DE DÉTECTION UTILISANT LE SYSTÈME


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 25.06.2014 CN 201410291326

(43)Date of publication of application:
30.12.2015 Bulletin 2015/53

(73)Proprietors:
  • Tsinghua University
    Haidian District Beijing 100084 (CN)
  • Nuctech Company Limited
    TongFang Building, Shuangqinglu, Haidian District Beijing 100084 (CN)

(72)Inventors:
  • CHEN, Zhiqiang
    100084 BEIJING (CN)
  • ZHANG, Li
    100084 BEIJING (CN)
  • JIN, Xin
    100084 BEIJING (CN)
  • HUANG, Qingping
    100084 BEIJING (CN)
  • SHEN, Le
    100084 BEIJING (CN)
  • SUN, Yunda
    100084 BEIJING (CN)

(74)Representative: Delumeau, François Guy et al
Cabinet Beau de Loménie 158, rue de l'Université
75340 Paris Cedex 07
75340 Paris Cedex 07 (FR)


(56)References cited: : 
EP-A1- 2 437 051
US-A1- 2012 236 987
WO-A1-2009/073284
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    Field of the Invention



    [0001] The present disclosure relates to the technical field of dual energy CT detection, in particular, relates to a detector device for a dual energy CT system and a dual energy CT system including the detector device

    Description of the Related Art



    [0002] At present, a computer tomography technology (hereinafter referred to as CT technology) based on X-ray radiation imaging is widely used for security inspection, in particular, for inspecting suspicious articles in baggage. In the CT scanning technology based on X-ray radiation imaging, data for characteristic distribution of an object to be scanned in the tomography imaging is obtained by CT data reconstruction. Analysis of such characteristic data contributes to identification of common suspect substance in the baggage. A conventional CT apparatus includes an X-ray source, a collimating device, a rotatable slip-ring, detection units, a dedicated computer system for data calculation, power and control subsystems, etc..

    [0003] In a conventional dual energy CT structure, the detection unit usually comprises detection crystal units having different energy responses, that is, detection crystal units having a first energy response (e.g., low energy detection crystal units) and detection crystal units having a second energy response (e.g., high energy detection crystal units). Usually, the number of the detection crystal units having a first energy response is equal to that of the detection crystal units having a second energy response. The two types of detection crystal units are provided on two sides of a printed circuit board, respectively. When viewed from incidence direction of the ray, the two types of detection crystal units are aligned with each other (i.e., overlapped) with the printed circuit board being sandwiched therebetween, and the respective detection crystal units having a first energy response corresponds to the respective detection crystal units having a second energy response. During detection, an acquisition module is used to acquire data signals from the detection units, and the acquired data signals are decomposed into data from the detection crystal units having a first energy response and data from the detection crystal units having a second energy response by a dual energy decomposition technology, so as to reconstruct attenuation coefficient images, electron density images and atomic number images of the object in X-ray scanning with different energies. In this way, substance components can be identified and prohibited substance, such as drugs, explosives or the like, can be detected.

    [0004] For dual energy CT security inspection, sharpness of three-dimension images and identification accuracy of substance are key factors for imaging. However, these two factors require the detector units in different ways. In order to improve sharpness of three-dimension images, it is necessary to increase the number of the detection crystal units having a first energy response or the detection crystal units having a second energy response. However, in order to improve identification accuracy of substance, it is necessary to increase the numbers of the detection crystal units having a first energy response and of the detection crystal units having a second energy response. Furthermore, the number of crystals required for improving sharpness of three-dimension images is much greater than the number of crystal required for improving identification accuracy of substance.

    [0005] Therefore, in respect that detector crystals are expensive, it is desired to optimize an overall cost of a detector and to ensure a high spatial resolution for CT image reconstruction while meeting requirements for identification accuracy of substance.

    [0006] US2012/236987 describes multiple-energy CT scanning systems of different designs. In one discussed design, detector elements of different types are laid out adjacent to one another in a pattern resembling a chessboard.

    [0007] EP 2 437 051 describes a pseudo dual-energy scanning system for material identification. Variants are described in which detector elements are arranged in one or two tiers. In the two-tier arrangement the detector elements of the first tier are aligned with detector elements of the second tier.

    [0008] WO2009/073824 describes a CT system making use of a filter having an alternating pattern, disposed between the x-ray source and the detector. The filter is configured to facilitate measurement of data useable to generate low-energy and high--energy spectral information.

    SUMMARY OF THE INVENTION



    [0009] In view of the above, the present disclosure aims to solve at least one of the above-mentioned problems and defects existing in the prior art.

    [0010] An object of the present disclosure is to provide a novel detector device for a dual energy CT system, which has such an arrangement that detection crystal units having a first energy response and detection crystal units having a second energy response are alternatively disposed, so that optimization of detection cost can be realized, and a high spatial resolution for CT image reconstruction can be ensured while meeting requirements for identification accuracy of scanned substance. This detector device may be used to inspect suspicious objects in baggage.

    [0011] According to an aspect of the present disclosure, there is provided a detector device for a dual energy CT system, the detector device comprises a plurality of detector assemblies and a mounting plate, each detector assembly comprising:

    a plurality of detection crystal units having a first energy response which are arranged on a side of the mounting plate along a first direction at intervals, each detection crystal unit having a first energy response including a plurality of detection crystals having a first energy response arranged along a second direction, wherein the second direction is perpendicular to the first direction; and

    a plurality of detection crystal units having a second energy response which are arranged on the other side of the mounting plate along the first direction at intervals, each detection crystal unit having a second energy response including a plurality of detection crystals having a second energy response arranged along the second direction, wherein the second energy is higher than the first energy;

    wherein the plurality of detection crystal units having a first energy response and the plurality of detection crystal units having a second energy response are, at least partially, alternatively arranged along the first direction when viewed from an incidence direction of the X-ray;

    wherein the number of the detection crystal units having a first energy response is equal to or greater than that of the detection crystal units having a second energy response.



    [0012] It should be noted that the feature or disclosure of "the second energy is higher than the first energy" described throughout means "the second equivalent (or average) energy corresponding to the second energy response is higher than the first equivalent (or average) energy corresponding to the first energy response".

    [0013] With the detector device according to the present disclosure, since the detection crystal units having a first energy response and the detection crystal units having a second energy response are, at least partially, alternatively arranged (i.e., are arranged not to be aligned) along the first direction, in a mode of single energy processing, the spatial sampling locations for detecting the X-ray are increased, compared to the conventional arrangement in which the detection crystal units having a second energy response and the detection crystal units having a first energy response are arranged to be aligned with each other. A part of the X-ray emitted from the X-ray source is acquired by either of the detection crystal units having a first energy response and the detection crystal units having a second energy response that are alternatively arranged, and the rest of the X-ray is acquired by the detection crystal units having a first energy response and the detection crystal units having a second energy response that are aligned with each other. Then, all the acquired data signals are used for CT image reconstruction of the scanned object, so that spatial resolution can be enhanced. Furthermore, since the number of the detection crystal units having a second energy response are not increased, manufacturing cost for the detector device will not be increased significantly.

    [0014] In a specific embodiment, the number of the detection crystal units having a first energy response is equal to that of the detection crystal units having a second energy response.

    [0015] Further, since difference in manufacturing cost between the detection crystals having a first energy response and the detection crystals having a second energy response is great, when the cost of the detection crystals having a first energy response is much lower than that of the detection crystals having a second energy response, the number of the detection crystal units having a first energy response may be greater than that of the detection crystal units having a second energy response. Therefore, the spatial resolution for CT image reconstruction can be enhanced by increasing the number of the detection crystal units having a first energy response, without increasing the manufacturing cost of the detector device significantly.

    [0016] Further, the at least one detection crystal units having a first energy response and the at least one detection crystal units having a second energy response are arranged along the first direction in an entirely alternative arrangement (i.e., the two types of detection crystal units are not aligned with each other in the first direction). Such arrangement means that in the mode of single energy processing, the spatial sampling locations for X-ray detection are further increased by alternatively arranging all the detection crystal units having a first energy response and a second energy response, without changing the total number of the detection crystal units (i.e., without increasing the total manufacturing cost).

    [0017] In an embodiment, the plurality of detector assemblies are arranged on a circular arc-shaped support centered at a center of the scanning tunnel or on an approximate circular arc-shaped support consisting of a plurality of straight members and centered at the center of the scanning tunnel. Specifically, the detector assemblies of the detector device for the dual energy CT system described in the present disclosure may be arranged in the arrangement disclosed in the Chinese Patent Application No. 201210350516.X (title: CT SECURITY INSPECTION SYSTEM FOR BAGGAGE AND DETECTOR ARRANGEMENT THEREOF).

    [0018] Alternatively, the plurality of detector assemblies may be arranged on a circular arc-shaped support centered at the X-ray source or an approximate circular arc-shaped support consisting of a plurality of straight members.

    [0019] Alternatively, the plurality of detector assemblies may be arranged on the circular arc-shaped or approximate circular arc-shaped support in a spiral manner, so that a detection path for detecting the scanned object is a spiral path when the scanned object is transported to pass through a scanning plane.

    [0020] In a preferred embodiment, incidence surfaces of the detection crystal units having a first energy response and/or the detection crystal units having a second energy response may be provided thereon with filtering layers for adjusting energy response of the detection crystal units.

    [0021] In the claimed embodiments, the detector device comprises a mounting plate. The detection crystal units having a first energy response are arranged on a side of the mounting plate in such manner that the detection crystal units having a first energy response are arranged along the first direction at intervals, and the detection crystal units having a second energy response are arranged on the other side of the mounting plate in such manner that the detection crystal units having a second energy response are arranged along the first direction at intervals.

    [0022] Preferably, the X-ray source is a single light source or a distributed multi-beam source.

    [0023] According to another aspect of the present disclosure, there is provided a detector device for a dual energy CT system. The detector device comprises a plurality of detector assemblies and a mounting plate. Each detector assembly comprises a plurality of detection crystal units having a first energy response arranged on a side of the mounting plate along a first direction at intervals, and each detection crystal unit having a first energy response comprises a plurality of detection crystals having a first energy response arranged along the second direction, wherein the second direction is perpendicular to the first direction; and
    a plurality of detection crystal units having a second energy response arranged on the other side of the mounting plate along the first direction at intervals, and each detection crystal unit having a second energy response comprises a plurality of detection crystals having a second energy response arranged along the second direction, wherein the second energy is higher than the first energy;
    wherein the number of the detection crystal units having a second energy response is less than that of the detection crystal units having a first energy response, and when viewed from an incidence direction of the X-ray, some of the detection crystal units having a first energy response correspond to and are arranged to be overlapped with respective detection crystal units of the plurality of detection crystal units having a second energy response.

    [0024] As described above, since the cost of the detection crystal having a first energy response (e.g., the low energy detection crystal) is much lower than that of the detection crystal having a second energy response (e.g., the high energy detection crystal), sharpness of three-dimension images can be enhanced by increasing the number of the detection crystal units having a first energy response. Meanwhile, since the number of the detection crystals required for meeting accuracy requirements of substance identification is much less than the number of the detection crystals required for meeting sharpness requirements of three-dimension images, a small amount of the detection crystal units having a second energy response can be provided. Thus, detection cost can be optimized, and a higher spatial resolution for CT image reconstruction can be ensured while meeting accuracy requirements of substance identification.

    [0025] According to a further aspect of the present disclosure, there is provided a dual energy CT system, comprising a scanning tunnel through which an object to be scanned, such as baggage, enters and exits the dual energy CT system along a transporting direction, an X-ray source provided at a side of the scanning tunnel, and a gantry provided at an opposite side of the scanning tunnel. The above-described detector device is mounted on the gantry.

    [0026] In an embodiment, the dual energy CT system further comprises an acquisition module for acquiring data signals from the plurality of detector assemblies and a control module for controlling radiation emission of the X-ray source and the data signal acquisition operation, and the control module and the acquisition module are mounted within the same gantry.

    [0027] In an embodiment, the dual energy CT system according to the present disclosure further comprises a data processing module. The data processing module is configured to perform a first data processing and a second data processing. In the first data processing, a single energy processing mode is used, and all the acquired data signals are used to reconstruct CT images of the scanned object. In the second data processing, a dual energy processing mode is used, and the acquired data signals are decomposed into data signals from the at least one detection crystal units having a first energy response and data signals from the at least one detection crystal units having a second energy response. Then, the decomposed data signals are used for reconstruction to obtain attenuation coefficient images, electron density images and atomic number images of the scanned article in X-ray scanning with different energies.

    [0028] In a specific embodiment, the data processing module may be configured to, in the second data processing, employ interpolation algorithms to obtain dual energy projection data which correspond to an alignment arrangement and then perform reconstruction of attenuation coefficient images, electron density images and atomic number images in X-ray scanning with different energies in the case where the detection crystal units having a second energy response and the detection crystal units having a first energy response are alternatively arranged. With such configuration, the problem that the dual energy decomposition cannot be directly realized due to misalignment of the detection crystal units having a first energy response and a second energy response can be solved.

    [0029] There is a CT detection method using the above-described dual energy CT system, comprising the steps of: transporting
    the object to be scanned (e.g., baggage) through the scanning tunnel; driving the gantry to rotate and at the same time controlling the X-ray source to emit the X-ray; acquiring data signals from the plurality of detector assemblies; and performing a first data signal processing and a second data signal processing, wherein in the first data processing, a single energy processing mode is used, and the acquired data signals are used to reconstruct CT images of the scanned object, and in the second data processing, a dual energy processing mode is used, and the acquired data signals are decomposed into data signals from the at least one detection crystal units having a first energy response and data signals from the at least one detection crystal units having a second energy response. Then, the decomposed data signals are used for reconstruction to obtain the attenuation coefficient images, the electron density images and the atomic number images of the scanned article in X-ray scanning with different energies.

    [0030] In the second data processing, an interpolation algorithm is employed to obtain dual energy projection data which correspond to
    an alignment arrangement and then perform reconstruction of the attenuation coefficient images, the electron density images and the atomic number images in X-ray scanning with different energies in the case where the detection crystal units having a second energy response and the detection crystal units having a first energy response are alternatively arranged.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0031] The above and other features of the dual energy CT system and the detector assemblies used in the same according to the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings by way of examples. Throughout the drawings, same reference numerals represent same or similar members.

    Fig. 1 is a schematic view of an overall dual energy CT system according to an embodiment of the present disclosure;

    Fig. 2 is a schematic perspective view of main components of the dual energy CT system;

    Figs. 3a-3e show exemplary arrangements of the detection crystal units having a first energy response and the detection crystal units having a second energy response in the detector assemblies of the detector device according to the present disclosure; and

    Fig. 4 is a top view showing a schematic structure view of the detector device.


    DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION



    [0032] Embodiments of the present disclosure will be further explained below with reference to the accompanying drawings. It should be noted that same or similar reference numerals represent same or similar members or those having same or similar functions. The following embodiments are only explained by way of examples, instead of being intended to limit the scope of the present invention.

    [0033] Referring to Fig. 1, it shows a dual energy CT (computer tomography) system according to an exemplary embodiment of the present disclosure. Such system may be used for inspecting suspicious articles, for example, in baggage. The dual energy CT system comprises a scanning entrance tunnel 2 and a scanning exit tunnel 6 through which an object to be scanned (not shown), such as baggage, enters and exits the dual energy CT system along a transporting direction shown at arrow A, an X-ray source 8 provided between the scanning entrance tunnel 2 and the scanning exit tunnel 6, a gantry 5 provided at an opposite side to the X-ray source 8. A detector device 20 is mounted on the gantry 5, and the detector device 20 comprises a plurality of detector assemblies 21. In one preferred embodiment, the dual energy CT system further comprises a slip-ring subsystem 3 disposed around the scanning tunnel, and the X-ray source 8 and the gantry 5 are mounted on the slip-ring subsystem 3 and are rotatable about the center of the scanning tunnel.

    [0034] As shown in Fig. 2, in the above-mentioned CT system, the gantry 5 is mounted on a rotatable gantry-mounting plate 12 of the slip-ring subsystem 3 for mounting the gantry 5, and the gantry-mounting plate 12 is mounted in slip-ring supporting frame 13 and is driven by a slip-ring driving motor 14. Also, the detector device 20, the X-ray source 8, a first collimator 9 and a second collimator 10 are mounted on the gantry 5. In this embodiment, there is only one gantry 5 in this system. The gantry 5 is a closed structure in which a data acquisition/control module 34 is mounted. The whole CT data acquisition system can employ a set of data acquisition module and control module. Further, all the acquired data can be processed by one type of algorithm, so that a speed for performing a scanning operation in the CT system can be increased and a data transferring and processing speed can also be increased.

    [0035] Referring to Figs. 3(a)-(d), exemplary arrangements of detection crystal units 22 having a first energy response and detection crystal units 23 having a second energy response in the detector assembly 21 of the detector device 20 according to the present disclosure are illustratively shown. In an embodiment, the detection crystal unit having a first energy response is a low energy detection crystal unit consisting of at least one low energy detection crystal, and the detection crystal unit having a second energy response is a high energy detection crystal unit consisting of at least one high energy detection crystal. According to the present disclosure, each detector assembly 21 comprises at least one detection crystal units 22 having a first energy response arranged along a first direction (as shown at arrow B) at intervals, and each detection crystal unit 22 having a first energy response comprises at least one detection crystals 22a, 22b, 22c... having a first energy response arranged along a second direction. The second direction (as shown at arrow C) is perpendicular to the first direction. The detector assembly 21 also comprises at least one detection crystal units 23 having a second energy response arranged along the first direction at intervals, and each detection crystal unit 23 having a second energy response comprises at least one detection crystals 23a... having a second energy response arranged along the second direction. The second energy is higher than the first energy. When viewed from an incidence direction of the X-ray, the at least one detection crystal units 22 having a first energy response and the at least one detection crystal units 23 having a second energy response are, at least partially, alternatively arranged along the first direction. For instance, one detection crystal unit having a first energy response and one detection crystal unit having a second energy response are alternatively arranged along the first direction and are not aligned with each other.

    [0036] One skilled in the art of detection using detection crystals can understand that the feature or disclosure of "the second energy is higher than the first energy" described herein substantively means "the second equivalent (or average) energy corresponding to the second energy response is higher than the first equivalent (or average) energy corresponding to the first energy response". In other words, the feature or disclosure of "the second energy is higher than the first energy" described herein substantively relates to comparison of equivalent energies or average energies corresponding to the respective energy responses.

    [0037] With such detector device, since the detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response are, at least partially, alternatively arranged along the first direction, in a mode of single energy processing, the spatial sampling locations for detecting the X-ray are increased, compared to the conventional arrangement in which the detection crystal units having a second energy response and the detection crystal units having a first energy response are arranged to be aligned with each other. A part of the X-ray emitted from the X-ray source is acquired by either of the detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response that are alternatively arranged, and the rest of the X-ray is acquired by the detection crystal units having a first energy response and the detection crystal units having a second energy response that are aligned with each other. Then, all the acquired data signals are used for CT image reconstruction of the scanned object, so that spatial resolution can be enhanced. Furthermore, since the number of the detection crystal units 23 having a second energy response is not increased, manufacturing cost for the detector device will not be increased.

    [0038] In a specific embodiment, the number of the detection crystal units 22 having a first energy response may be equal to that of the detection crystal units 23 having a second energy response, for example, as shown in Fig. 3(a). The number of the detection crystal units 22 having a first energy response may be equal to that of the detection crystal units 23 having a second energy response, for example, as shown in Figs. 3(b)-3(d). Since the cost of the detection crystal having a first energy response is much lower than that of the detection crystal having a second energy response, spatial resolution for CT image reconstruction can be enhanced by increasing the number of the detection crystal units having a first energy response, and thus the manufacturing cost of the detector device will not be evidently increased.

    [0039] The detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response may be arranged in an entirely alternative manner, that is, any of the detection crystal units 22 having a first energy response is not aligned with any of the detection crystal units 23 having a second energy response, as shown in Figs. 3(a)-3(d). Such arrangement means that in the mode of single energy processing, the spatial sampling locations for X-ray detection are further increased by alternatively arranging all the detection crystal units having a first energy response and a second energy response, without changing the total number of the detection crystal units (i.e., without increasing the total manufacturing cost), thereby further enhancing the spatial resolution for CT image reconstruction.

    [0040] Fig. 3(e) shows an another exemplary arrangement of the detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response in the detector assembly 21 of the detector device 20 according to the present disclosure. In this exemplary arrangement, each detector assembly 21 comprises at least two detection crystal units 22 having a first energy response arranged along the first direction at intervals, and each detection crystal unit 22 having a first energy response comprises at least one detection crystals 22a, 22b, 22c... having a first energy response arranged along the second direction. The first direction is parallel to the transporting direction of the scanned object. The second direction is perpendicular to the first direction. The detector assembly 21 also comprises at least one detection crystal units 23 having a second energy response arranged along the first direction at intervals, and each detection crystal unit 23 having a second energy response comprises at least one detection crystals 23a... having a second energy response arranged along the second direction. The second energy is higher than the first energy. The number of the detection crystal units 23 having a second energy response is less than that of the detection crystal units 22 having a first energy response. When viewed from an incidence direction of the X-ray, some of the at least two detection crystal units 22 having a first energy response correspond to and are arranged to be aligned with respective detection crystal units of the at least one detection crystal units 23 having a second energy response.

    [0041] In this way, on one hand, sharpness of three-dimension images can be enhanced by increasing the number of the detection crystal units 22 having a first energy response; on the other hand, since the number of the detection crystals required for meeting accuracy requirements of substance identification is much less than the number of the detection crystals required for meeting sharpness requirements of three-dimension images, providing a small amount of the detection crystal units 23 having a second energy response will not bring any adverse influence on substance identification. Therefore, detection cost can be optimized, and a higher spatial resolution for CT image reconstruction can be ensured while meeting accuracy requirements of substance identification.

    [0042] As exemplarily shown in Figs. 3(a)-(e), in an embodiment, the detector device further comprises a mounting plate 24. The detection crystal units having a first energy response are arranged on a side of the mounting plate 24 in such manner that the detection crystal units having a first energy response are arranged along the first direction at intervals, and the detection crystal units having a second energy response are arranged on the other side of the mounting plate 24 in such manner that the detection crystal units having a second energy response are arranged along the first direction at intervals. Alternatively, the at least one detection crystal units having a first energy response and the at least one detection crystal units having a second energy response are mounted on the same or different sides of different mounting plates. In an embodiment, the mounting plate 24 may be a printed circuit board, and a circuit corresponding to the detection crystal units is provided on the printed circuit board.

    [0043] In a preferred embodiment, an incidence surface of the detection crystal unit in the detector assembly as shown in Figs. 3(a)-(e) may be provided with a filtering layer (not shown), such as a copper layer, for adjusting an energy response of the detection crystal unit. In an embodiment, the X-ray source is a single light source or a distributed multi-beam source.

    [0044] An improved arrangement of detector assemblies was disclosed in Chinese Patent Application No. 201210350516.X (CT SECURITY INSPECTION SYSTEM FOR BAGGAGE AND DETECTOR ARRANGEMENT THEREOF) owned by the applicant of the present application. The plurality of detector assemblies described in the present disclosure may be arranged in the arrangement disclosed in the Chinese Patent Application No. 201210350516.X, so as to reduce the size of the CT security inspection system and to improve scan efficiency. Specifically, the plurality of detector assemblies 21 may be arranged on a circular arc-shaped support centered at a center of the scanning tunnel or on an approximate circular arc-shaped support consisting of a plurality of straight members. However, it should be noted that the plurality of detector assemblies may be arranged on a circular arc-shaped support centered at the X-ray source or an approximate circular arc-shaped support consisting of a plurality of straight members in a conventional way.

    [0045] In an embodiment, the plurality of detector assemblies may be arranged on the circular arc-shaped or approximate circular arc-shaped support in a spiral manner, so that a detection path for detecting the scanned object is a spiral path when the scanned object is transported to pass through a scanning plane. The spiral path is defined as a spatial path through which a fixed point (such as a light source and the like) on the slip-ring passes when the scanned object is transported to pass through the scanning plane, with the scanned object being taken as a resting reference. Specifically, referring to Fig. 2, in the plurality of detector assemblies, for example, in the order of from left to right/from right to left, one detector assembly is moved toward a page-in direction/a page-out direction in sequence by a distance relative to another adjacent detector assembly.

    [0046] In an embodiment, the dual energy CT system according to the present disclosure further comprises a data processing module (not shown). The data processing module may be integrated on the dual energy CT system, or may be separately provided. The data processing module is configured to perform a first data processing and a second data processing. In the first data processing, a single energy processing mode is used, and data signals from the detection crystal units 23 having a second energy response, data signals from the detection crystal units 22 having a first energy response and data signals from a unit block formed by the detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response that are aligned with each other are not distinguished. All the acquired data signals are used to reconstruct CT images of the scanned object, such as baggage, so as to detect prohibited articles, such as knives or weapon. In the second data processing, a dual energy processing mode is used, and the acquired data signals are decomposed into data signals from the at least one detection crystal units 22 having a first energy response and data signals from the at least one detection crystal units 23 having a second energy response by a dual energy decomposition technique. Then, the decomposed data signals are used for reconstruction to obtain attenuation coefficient images, electron density images and atomic number images of the scanned article in X-ray scanning with different energies, so as to identify substance and detect prohibited articles, such as drugs or explosives.

    [0047] As one skilled in the art can know, in a case where the detection crystal units 22 having a first energy response and the detection crystal units 23 having a second energy response are arranged in an entirely alternative manner or are arranged in a partially alternative manner, the dual energy decomposition cannot be directly realized because some of the detection crystal units having a first energy response and a second energy response are not aligned with each other. Accordingly, the inventors propose that the data processing module can be configured to employ interpolation algorithms to obtain dual energy projection data which correspond to an alignment arrangement and then reconstruct the electron density images and the atomic number images in the case where the detection crystal units 23 having a second energy response and the detection crystal units 22 having a first energy response are, at least partially, alternatively arranged, during performing the second data processing. With such configuration, the above-mentioned problem that the dual energy decomposition cannot be directly realized due to misalignment of the detection crystal units 23 having a second energy response and the detection crystal units 22 having a first energy response can be solved.

    [0048] Fig. 4 is a top view showing a schematic structure view of the dual energy CT system according to the present disclosure. The dual energy CT system further comprises the first collimator 9 and the second collimator 10. The first collimator 9 includes collimator grids 39 for decomposing the ray emitted by the X-ray source 8 and controlling energy intensity of X-ray beams outputted from each of the grids. The second collimator 10 includes grids 37 for shielding the X-ray incident onto the detector assemblies such that the X-ray arriving at a detector crystal receiving face can be ensured to come from a major face of the detection crystal, instead of being scattered by edges of the detector crystal receiving face. As shown in Fig. 4, the grids 39 of the first collimator 9 include at least two partitions for decomposing the ray emitted by the X-ray source 8 into two or more sector ray beams. Further, as shown in Fig. 4, along the direction of the scanning tunnel 2 or 6, the respective decomposed sector ray beams correspond to respective receiving faces of the plurality of detection crystal units 22 and 23 so as to synchronously acquire data from a plurality of columns of detectors along the direction of the scanning tunnel 2 or 6. The plurality of detector assemblies 21 may consist of a plurality of detector crystal units mounted within a detector mounting case 35 through a detector crystal mounting bracket. The detector mounting case is sealed to reduce disturbance on performance of the detector crystals caused by light, dust and environmental humidity. The detector mounting case 35 is mounted on the CT gantry by an attachment support 42. In order to reduce shielding of the ray beams in the main direction while ensuring sealing and shading, a dustproof shadow shield 38 is mounted at a position in front of the detector crystal receiving faces, towards the target of the X-ray source. Preferably, the thickness of the dustproof shadow shield 38 is not greater than 3mm. The dustproof shadow shield is made of light-weight material, including but not limited to Teflon, plastics, bakelite and aluminum foil. In the preferred embodiment, the collimator grids 39 of the first collimator are embodied as one or more dotted fitting curves related to distribution of ray energy, wherein slits of some of the grids in the middle are relatively narrow while slits of some of the grids in the margin are relatively wide, such that energy intensities reaching the different detector crystal receiving faces are substantially same. In a specific embodiment, the collimator grids 39 of the first collimator is provided with a plurality of slits, at least two, e.g., three as shown in Fig. 4.

    [0049] Brief description on specific operation of the dual energy CT system according to the present disclosure will be introduced in the followings. Through the scanning entrance tunnel 2, the object to be scanned (not shown), such as baggage, is transported into the dual energy CT system. Meanwhile, a light barrier at the entrance is actuated, and with acquisition commands issued by a system controlling module, the slip-ring 3 is driven by the slip-ring driving motor 14 to rotate and hence the gantry 5 starts to rotate along with rotation of the slip-ring 3. The X-ray emitted by the X-ray source 8 in the CT system passes through the first collimator 9 which is used as a front energy collimating device, and the latter splits the energy ray into a plurality of columns of sector X-ray beams. Then, the detector assemblies 21 begin to acquire the data on these X-ray beams. Finally, the acquired data is used for reconstruction by the data processing module. Specifically, the data processing module is configured to perform a first data processing and a second data processing. In the first data processing, a single energy processing mode is used, and all the acquired data signals are used to reconstruct CT images of the scanned object, such as baggage, to obtain the structure and the shape images of the scanned object, thereby detecting prohibited articles, such as knives or weapon. In the second data processing, a dual energy processing mode is used, and the acquired data signals are decomposed into data signals from the at least one detection crystal units 22 having a first energy response and data signals from the at least one detection crystal units 23 having a second energy response by, for example, a conventional dual energy decomposition technique. Then, the decomposed data signals are used for reconstruction to obtain attenuation coefficient images, electron density images and atomic number images of the scanned article in X-ray scanning with different energies, so as to identify substance and detect prohibited articles, such as drugs or explosives. In a preferred embodiment, in the second data processing, interpolation algorithms are employed to obtain dual energy projection data which correspond to an alignment arrangement and then reconstruct the electron density images and the atomic number images in the case where the detection crystal units 23 having a second energy response and the detection crystal units 22 having a first energy response are, at least partially, alternatively arranged.

    [0050] Although several exemplary embodiments have been shown and described, the present invention is not limited to those and it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles of the disclosure, which should fall within the scope of the present invention. The scope of the invention is defined by the claims.


    Claims

    1. A detector device for a dual energy CT system, the detector device comprises a plurality of detector assemblies and a mounting plate (24), each detector assembly (21) comprising:

    a plurality of detection crystal units (22) having a first energy response which are arranged on a side of the mounting plate (24) along a first direction (B) at intervals, each detection crystal unit having a first energy response including a plurality of detection crystals (22a, 22b, 22c) having a first energy response arranged along a second direction (C), wherein the second direction is perpendicular to the first direction; and

    a plurality of detection crystal units (23) having a second energy response which are arranged on the other side of the mounting plate (24) along the first direction at intervals, each detection crystal unit having a second energy response including a plurality of detection crystals having a second energy response arranged along the second direction, wherein the second energy is higher than the first energy;

    wherein the plurality of detection crystal units having a first energy response and the plurality of detection crystal units having a second energy response are, at least partially, alternatively arranged along the first direction when viewed from an incidence direction of the X-ray;

    wherein the number of the detection crystal units having a first energy response is equal to or greater than that of the detection crystal units having a second energy response.


     
    2. The detector device for the dual energy CT system according to claim 1, wherein when viewed from the incidence direction of the X-ray, the plurality of detection crystal units (22) having a first energy response and the plurality of detection crystal units (23) having a second energy response are arranged along the first direction in an entirely alternative arrangement.
     
    3. The detector device for the dual energy CT system according to claim 1, wherein the plurality of detector assemblies are arranged on a circular arc-shaped support centered at a center of a scanning tunnel or an x-ray source of the dual energy CT system or an approximate circular arc-shaped support consisting of a plurality of straight members in a spiral manner, so that a detection path for detecting the scanned object is a spiral path when the scanned object is transported to pass through a scanning plane.
     
    4. The detector device for the dual energy CT system according to claim 1, wherein incidence surfaces of the detection crystal units having a first energy response and/or the detection crystal units having a second energy response are provided thereon with filtering layers for adjusting the energy response of the detection crystal units.
     
    5. A detector device for a dual energy CT system, wherein the detector device comprises a plurality of detector assemblies and a mounting plate, each detector assembly comprising:

    a plurality of detection crystal units having a first energy response arranged on a side of the mounting plate along a first direction at intervals, and each detection crystal unit having a first energy response comprises a plurality of detection crystals having a first energy response arranged along the second direction, wherein the second direction is perpendicular to the first direction; and

    a plurality of detection crystal units having a second energy response arranged on the other side of the mounting plate along the first direction at intervals, and each detection crystal unit having a second energy response comprises a plurality of detection crystals having a second energy response arranged along the second direction, wherein the second energy is higher than the first energy;

    wherein the number of the detection crystal units having a second energy response is less than that of the detection crystal units having a first energy response, and when viewed from an incidence direction of the X-ray, some of the detection crystal units having a first energy response correspond to and are arranged to be overlapped with respective detection crystal units of the plurality of detection crystal units having a second energy response.


     
    6. The detector device for the dual energy CT system according to claim 5, wherein the plurality of detector assemblies are arranged on a circular arc-shaped support centered at a center of a scanning tunnel or an x-ray source of the dual energy CT system or an approximate circular arc-shaped support consisting of a plurality of straight members in a spiral manner, so that a detection path for detecting the scanned object is a spiral path when the scanned object is transported to pass through a scanning plane.
     
    7. The detector device for the dual energy CT system according to claim 5, wherein incidence surfaces of the detection crystal units having a first energy response and/or the detection crystal units having a second energy response are provided thereon with filtering layers for adjusting the energy response of the detection crystal units.
     
    8. A dual energy CT system, comprising:

    a scanning tunnel (2, 6) through which an object to be scanned enters/exits the dual energy CT system along a transporting direction;

    an X-ray source (8) provided at a side of the scanning tunnel; and

    a gantry (5) provided at an opposite side of the scanning tunnel;

    wherein the detector device according to any one of claims 1-7 is mounted on the gantry.


     
    9. The dual energy CT system according to claim 8, further comprising:

    an acquisition module for acquiring data signals from the plurality of detector assemblies; and

    a control module for controlling radiation emission of the X-ray source and the data signal acquisition operation,

    wherein the control module and the acquisition module are mounted within the same gantry;

    and/or, further comprising a data processing module, and the data processing module is configured to perform a first data processing and a second data processing,

    wherein in the first data processing, a single energy processing mode is used, and all the acquired data signals are used to reconstruct CT images of the scanned object; in the second data processing, a dual energy processing mode is used, and the acquired data signals are decomposed into data signals from the plurality of detection crystal units having a first energy response and data signals from the plurality of detection crystal units having a second energy response, and the decomposed data signals are used for reconstruction to obtain attenuation coefficient images, electron density images and atomic number images of the scanned article in X-ray scanning with different energies.


     
    10. The dual energy CT system according to claim 9, wherein the data processing module is configured to, in the second data processing, employ interpolation algorithms to obtain dual energy projection data which correspond to an alignment arrangement and then perform reconstruction of attenuation coefficient images, electron density images and atomic number images in X-ray scanning with different energies in the case where the detection crystal units having a second energy response and the detection crystal units having a first energy response are alternatively arranged.
     


    Ansprüche

    1. Detektorvorrichtung für ein CT-System mit dualer Energie, wobei die Detektorvorrichtung eine Vielzahl von Detektoranordnungen und eine Befestigungsplatte (24) umfasst, wobei jede Detektoranordnung (21) umfasst:

    eine Vielzahl von Detektionskristall-Einheiten (22), die eine erste Energieantwort aufweisen, welche entlang einer ersten Richtung (B) auf einer Seite der Befestigungsplatte (24) in Abständen angeordnet sind, wobei jede Detektionskristall-Einheit, die eine erste Energieantwort aufweist, eine Vielzahl von Detektionskristallen (22a, 22b, 22c), die eine ersten Energieantwort aufweist, die entlang einer zweiten Richtung (C) angeordnet sind, wobei die zweite Richtung senkrecht zu der ersten Richtung ist, und

    eine Vielzahl von Detektionskristall-Einheiten (23), die eine zweite Energieantwort aufweisen, welche auf der anderen Seite der Befestigungsplatte (24) entlang der ersten Richtung in Abständen angeordnet sind, wobei jede Detektionskristall-Einheit, die eine zweite Energieantwort aufweist, eine Vielzahl von Detektionskristallen, die eine zweite Energieantwort aufweisen, umfasst, welche entlang der zweiten Richtung angeordnet sind, wobei die zweite Energie höher als die erste Energie ist,

    wobei die Vielzahl von Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, und die Vielzahl von Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, mindestens teilweise wechselseitig entlang der ersten Richtung angeordnet sind, wenn sie aus einer Einfallsrichtung der Röntgenstrahlung betrachtet werden,

    wobei die Anzahl der Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, gleich oder größer ist als die der Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen.


     
    2. Detektorvorrichtung für das CT-System mit dualer Energie nach Anspruch 1, wobei, wenn sie aus der Einfallsrichtung der Röntgenstrahlung betrachtet wird, die Vielzahl von Detektionskristall-Einheiten (22), die eine erste Energieantwort aufweisen, und die Vielzahl von Detektionskristall-Einheiten (23), die eine zweite Energieantwort aufweisen, entlang der ersten Richtung in einer vollständig wechselseitigen Anordnung angeordnet sind.
     
    3. Detektorvorrichtung für das CT-System mit dualer Energie nach Anspruch 1,
    wobei die Vielzahl von Detektoranordnungen auf einem kreisbogenförmigen Träger angeordnet sind, der in der Mitte eines Scannertunnels oder einer Röntgenstrahlenquelle des CT-Systems mit dualer Energie oder eines annähernd kreisbogenförmigen Trägers zentriert ist, der aus einer Vielzahl von geraden Elementen in einer spiralförmigen Weise besteht, sodass ein Detektionspfad zum Detektieren des gescannten Objekts eine Spiralbahn ist, wenn das gescannte Objekt transportiert wird, um durch eine Scanebene hindurchzugehen.
     
    4. Detektorvorrichtung für das CT-System mit dualer Energie nach Anspruch 1,
    wobei Einfallsflächen der Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, und/oder der Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, darauf mit Filterschichten zum Einstellen der Energieantwort der Detektionskristall-Einheiten versehen sind.
     
    5. Detektorvorrichtung für ein CT-System mit dualer Energie, wobei die Detektorvorrichtung eine Vielzahl von Detektoranordnungen und eine Befestigungsplatte umfasst, wobei jede Detektoranordnung umfasst:

    eine Vielzahl von Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, welche entlang einer ersten Richtung auf einer Seite der Befestigungsplatte in Abständen angeordnet sind, und jede Detektionskristall-Einheit, die eine erste Energieantwort aufweist, eine Vielzahl von Detektionskristallen mit einer ersten Energieantwort aufweist, die entlang der zweiten Richtung angeordnet sind, wobei die zweite Richtung senkrecht zu der ersten Richtung ist, und

    eine Vielzahl von Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, welche auf der anderen Seite der Befestigungsplatte entlang der ersten Richtung in Abständen angeordnet sind, und jede Detektionskristall-Einheit, die eine zweite Energieantwort aufweist, eine Vielzahl von Detektionskristallen, die eine zweite Energieantwort aufweisen, umfasst, welche entlang der zweiten Richtung angeordnet sind, wobei die zweite Energie höher als die erste Energie ist,

    wobei die Anzahl der Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, kleiner ist als die der Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, und wenn sie aus einer Einfallsrichtung des Röntgenstrahls betrachtet werden, entsprechen einige der Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, entsprechenden Detektionskristall-Einheiten der Vielzahl von Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, und sind so angeordnet, dass sie mit diesen überlappen.


     
    6. Detektorvorrichtung für das CT-System mit dualer Energie nach Anspruch 5, wobei die Vielzahl von Detektoranordnungen auf einem kreisbogenförmigen Träger angeordnet sind, der in der Mitte eines Scannertunnels oder einer Röntgenstrahlenquelle des CT-Systems mit dualer Energie oder eines annähernd kreisbogenförmigen Trägers zentriert ist, der aus einer Vielzahl von geraden Elementen in einer spiralförmigen Weise besteht, sodass ein Detektionspfad zum Detektieren des gescannten Objekts eine Spiralbahn ist, wenn das gescannte Objekt transportiert wird, um durch eine Scanebene hindurchzugehen.
     
    7. Detektorvorrichtung für das CT-System mit dualer Energie nach Anspruch 5, wobei Einfallsflächen der Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, und/oder der Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, darauf mit Filterschichten zum Einstellen der Energieantwort der Detektionskristall-Einheiten versehen sind.
     
    8. CT-System mit dualer Energie, umfassend:

    einen Scannertunnel (2, 6), durch den ein zu scannendes Objekt entlang einer Transportrichtung in das CT-System mit dualer Energie eintritt/ daraus austritt,

    eine Röntgenquelle (8), die an einer Seite des Scannertunnels vorgesehen ist, und

    eine Gantry (5), die an einer gegenüberliegenden Seite des Scannertunnels vorgesehen ist,

    wobei die Detektorvorrichtung nach einem der Ansprüche 1 bis 7 auf der Gantry befestigt ist.


     
    9. CT-System mit dualer Energie nach Anspruch 8, ferner umfassend:

    ein Erfassungsmodul zum Erfassen von Datensignalen aus der Vielzahl von Detektoranordnungen, und

    ein Steuermodul zum Steuern der Strahlungsemission der Röntgenstrahlenquelle und des Vorgangs der Datensignalerfassung,

    wobei das Steuermodul und das Erfassungsmodul innerhalb derselben Gantry befestigt sind,

    und/oder, ferner umfassend ein Datenverarbeitungsmodul, und wobei das Datenverarbeitungsmodul konfiguriert ist, um eine erste Datenverarbeitung und eine zweite Datenverarbeitung durchzuführen,

    wobei in der ersten Datenverarbeitung ein einzelner Energieverarbeitungsmodus verwendet wird und alle erfassten Datensignale verwendet werden, um CT-Bilder des gescannten Objekts zu rekonstruieren, wobei in der zweiten Datenverarbeitung ein dualer Energieverarbeitungsmodus verwendet wird und die erfassten Datensignale in Datensignale aus der Vielzahl von Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, und in Datensignale aus der Vielzahl von Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, zerlegt werden, und die zerlegten Datensignale zur Rekonstruktion verwendet werden, um Dämpfungskoeffizientenbilder, Elektronendichtebilder und Kernladungszahlbilder des gescannten Gegenstandes beim Röntgenscannen mit unterschiedlichen Energien zu erhalten.


     
    10. CT-System mit dualer Energie nach Anspruch 9, wobei das Datenverarbeitungsmodul konfiguriert ist, um in der zweiten Datenverarbeitung Interpolationsalgorithmen zum Erhalten von Projektionsdaten mit dualer Energie zu verwenden, die einer Ausrichtungsanordnung entsprechen, und dann eine Rekonstruktion von Dämpfungskoeffizientenbildern, Elektronendichtebildern und Kernladungszahlbildern beim Röntgenscannen mit unterschiedlichen Energien durchzuführen, in dem Fall, wo die Detektionskristall-Einheiten, die eine zweite Energieantwort aufweisen, und die Detektionskristall-Einheiten, die eine erste Energieantwort aufweisen, wechselseitig angeordnet sind.
     


    Revendications

    1. Dispositif de détection destiné à un système de tomodensitométrie à énergie double, le dispositif de détection comprenant une pluralité d'ensembles de détection et une plaque de montage (24), chaque ensemble de détection (21) comprenant :

    une pluralité d'unités à cristaux de détection (22) ayant une première réponse d'énergie qui sont disposées sur un côté de la plaque de montage (24) dans une première direction (B) à des intervalles, chaque unité à cristaux de détection ayant une première réponse d'énergie comprenant une pluralité de cristaux de détection (22a, 22b, 22c) ayant une première réponse d'énergie disposés dans une seconde direction (C), dans lequel la seconde direction est perpendiculaire à la première direction ; et

    une pluralité d'unités à cristaux de détection (23) ayant une seconde réponse d'énergie qui sont disposées sur l'autre côté de la plaque de montage (24) dans la première direction à des intervalles, chaque unité à cristaux de détection ayant une seconde réponse d'énergie comprenant une pluralité de cristaux de détection ayant une seconde réponse d'énergie disposés dans la seconde direction, dans lequel la seconde énergie est supérieure à la première énergie ;

    dans lequel la pluralité d'unités à cristaux de détection ayant une première réponse d'énergie et la pluralité d'unités à cristaux de détection ayant une seconde réponse d'énergie sont, au moins partiellement, disposées en alternance dans la première direction lorsque l'on regarde depuis une direction d'incidence des rayons X ;

    dans lequel le nombre d'unités à cristaux de détection ayant une première réponse d'énergie est égal ou supérieur à celui des unités à cristaux de détection ayant une seconde réponse d'énergie.


     
    2. Dispositif de détection destiné à un système de tomodensitométrie à énergie double selon la revendication 1, dans lequel, lorsqu'il est vu depuis la direction d'incidence des rayons X, la pluralité d'unités à cristaux de détection (22) ayant une première réponse d'énergie et la pluralité d'unités à cristaux de détection (23) ayant une seconde réponse d'énergie sont disposées dans la première direction selon un agencement entièrement alterné.
     
    3. Dispositif de détection destiné à un système de tomodensitométrie à énergie double selon la revendication 1, dans lequel la pluralité d'ensembles de détection est disposée sur un support en forme d'arc circulaire centré au niveau d'un centre d'un tunnel de balayage ou d'une source de rayons X du système de tomodensitométrie à énergie double ou sur un support en forme d'arc approximativement circulaire composé d'une pluralité d'éléments droits en spirale, de sorte qu'un trajet de détection destiné à détecter l'objet scanné soit un trajet en spirale lorsque l'objet scanné est transporté afin de traverser un plan de balayage.
     
    4. Dispositif de détection destiné à un système de tomodensitométrie à énergie double selon la revendication 1, dans lequel les surfaces d'incidence des unités à cristaux de détection ayant une première réponse d'énergie et/ou des unités à cristaux de détection ayant une seconde réponse d'énergie contiennent des couches de filtrage destinées à ajuster la réponse d'énergie des unités à cristaux de détection.
     
    5. Dispositif de détection destiné à un système de tomodensitométrie à énergie double, dans lequel le dispositif de détection comprend une pluralité d'ensembles de détection et une plaque de montage, chaque ensemble de détection comprenant :

    une pluralité d'unités à cristaux de détection ayant une première réponse d'énergie disposées sur un côté de la plaque de montage dans une première direction à des intervalles, et chaque unité à cristaux de détection ayant une première réponse d'énergie comprend une pluralité de cristaux de détection ayant une première réponse d'énergie disposées dans la seconde direction, dans lequel la seconde direction est perpendiculaire à la première direction ; et

    une pluralité d'unités à cristaux de détection ayant une seconde réponse d'énergie disposées sur l'autre côté de la plaque de montage dans la première direction à des intervalles, et chaque unité à cristaux de détection ayant une seconde réponse d'énergie comprenant une pluralité de cristaux de détection ayant une seconde réponse d'énergie disposés dans la seconde direction, dans lequel la seconde énergie est supérieure à la première énergie ;

    dans lequel le nombre d'unités à cristaux de détection ayant une seconde réponse d'énergie est inférieur à celui des unités à cristaux de détection ayant une première réponse d'énergie, et, lorsque l'on regarde depuis une direction d'incidence des rayons X, certaines des unités à cristaux de détection ayant une première réponse d'énergie correspondent à et sont disposées pour être chevauchées par les unités à cristaux de détection respectives de la pluralité d'unités à cristaux de détection ayant une seconde réponse d'énergie.


     
    6. Dispositif de détection destiné à un système de tomodensitométrie à énergie double selon la revendication 5, dans lequel la pluralité d'ensembles de détection est disposée sur un support en forme d'arc circulaire centré au niveau d'un centre d'un tunnel de balayage ou d'une source de rayons X du système de tomodensitométrie à énergie double, ou sur un support en forme d'arc approximativement circulaire composé d'une pluralité d'éléments droits en spirale, de sorte qu'un trajet de détection destiné à détecter l'objet scanné soit un trajet en spirale lorsque l'objet balayé est transporté afin de traverser un plan de balayage.
     
    7. Dispositif de détection destiné à un système de tomodensitométrie à énergie double selon la revendication 5, dans lequel les surfaces d'incidence des unités à cristaux de détection ayant une première réponse d'énergie et/ou des unités à cristaux de détection ayant une seconde réponse d'énergie contiennent des couches de filtrage destinées à ajuster la réponse d'énergie des unités à cristaux de détection.
     
    8. Système de tomodensitométrie à énergie double, comprenant :

    un tunnel de balayage (2, 6) par lequel un objet à balayer pénètre dans/sort du système de tomodensitométrie à énergie double dans une direction de transport ;

    une source de rayons X (8) prévue au niveau d'un côté du tunnel de balayage ; et

    un portique (5) prévu au niveau d'un côté opposé du tunnel de balayage ;

    dans lequel le dispositif de détection selon l'une quelconque des revendications 1 à 7 est monté sur le portique.


     
    9. Système de tomodensitométrie à énergie double selon la revendication 8, comprenant en outre :

    un module d'acquisition destiné à acquérir des signaux de données auprès de la pluralité d'ensembles de détection ; et

    un module de commande destiné à contrôler l'émission de rayonnement de la source de rayons X et l'opération d'acquisition du signal de données,

    dans lequel le module de commande et le module d'acquisition sont montés dans le même portique ;

    et/ou comprenant en outre un module de traitement de données, et le module de traitement de données est configuré pour effectuer un premier traitement de données et un second traitement de données,

    dans lequel, lors du premier traitement de données, un mode de traitement à énergie simple est utilisé, et tous les signaux de données acquis sont utilisés pour reconstruire des images de tomodensitométrie de l'objet scanné ; lors du second traitement de données, un mode de traitement à énergie double est utilisé, et les signaux de données acquis sont décomposés en signaux de données provenant de la pluralité d'unités à cristaux de détection ayant une première réponse d'énergie et en signaux de données provenant de la pluralité d'unités à cristaux de détection ayant une seconde réponse d'énergie, et les signaux de données décomposés sont utilisés pour la reconstruction afin d'obtenir des images de coefficient d'atténuation, des images de densité d'électrons et des images de nombre atomique de l'article scanné avec des rayons X à différentes énergies.


     
    10. Système de tomodensitométrie à énergie double selon la revendication 9, dans lequel le module de traitement de données est configuré pour, lors du second traitement de données, utiliser des algorithmes d'interpolation afin d'obtenir des données de projection à énergie double qui correspondent à un alignement, puis pour effectuer une reconstruction d'images de coefficient d'atténuation, d'images de densité d'électrons et d'images de nombre atomique lors d'un balayage à rayons X avec différentes énergies lorsque les unités à cristaux de détection ayant une seconde réponse d'énergie et les unités à cristaux de détection ayant une première réponse d'énergie sont disposées en alternance.
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description