X-ray system with modular two-layer detector

Abstract

The present invention relates to a detection system for an X-ray imaging system. The detection system comprises a first detector and a second detector, each detector having a detector region and configured to detect X-ray radiation emitted by the X-ray source of the X-ray imaging system that strikes its respective detection region. The detection system is configured to adjust the position of at least one of the first detector and the second detector relative to the other of the first detector and the second detector. The first detection region of the first detector and the second detection region of the second detector can be positioned at least partially behind the other with respect to the direction of X-ray radiation emitted from the X-ray source of the X-ray imaging system.

Description

Technical Field

[0001] The present invention relates to a detection system for an X-ray imaging system, an X-ray imaging system having the detection system, and a method of imaging an object using the X-ray imaging system.

Background Art

[0002] Imaging in the field of diagnostic or interventional X-ray imaging (DXR / IXR) is typically limited to detecting the linear attenuation coefficient mainly at the average energy of the X-ray beam. However, in the field of computed tomography, there is a tendency to shift to spectral imaging using various different methods such as dual-source imaging, two-layer detectors, high-speed kVp switching, or photon counting by energy discrimination. Spectral imaging makes it possible to distinguish two contributions to attenuation, namely photoelectric absorption and Compton scattering. This ultimately enables, for example, separating soft tissue in an image from iodine and leads to improved or simplified diagnosis in some tasks. A two-layer detector having two fixed layers used for energy separation to detect low-energy photons in the upper layer and high-energy photons in the lower layer can be used for spectral imaging. However, since spectral imaging is currently only for niche applications in DXR and IXR, large double-layer detectors are very expensive.

[0003] Therefore, the inventors of the present invention have found it advantageous to have an improved detection system for an X-ray imaging system that at least partially solves these problems and enables spectral X-ray imaging while reducing costs.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide an improved modular detection system for an X-ray imaging system that enables flexible adaptation of the detection area and spectral X-ray imaging in at least a part of the active detection area. [Means for solving the problem]

[0005] The object of the present invention is solved by the subject matter of the independent claim, and further embodiments are incorporated into the dependent claims.

[0006] The embodiments described also relate to a detection system for an X-ray imaging system, an X-ray imaging system including a detection system, and a method for imaging a target using the X-ray imaging system. The embodiments described further may be combined in any possible way. Although not described in detail, different combinations of embodiments may result in synergistic effects.

[0007] Furthermore, while all embodiments of the present invention relating to the method may be performed in the order of steps described, it should be noted that this is not the only and essential order of steps in the method. The methods described herein can be performed in a different order of steps without departing from the embodiments of each method, unless otherwise specified below.

[0008] According to a first aspect of the present invention, a detection system for an X-ray imaging system is provided. The detection system includes a first detector configured to detect X-ray radiation from an X-ray imaging system that strikes a first detection region of the first detector, and a second detector configured to detect X-ray radiation from an X-ray imaging system that strikes a second detection region of the second detector. The detection system is configured to adjust at least one position of the first detector and the second detector relative to the other of the first detector and the second detector so that, with respect to the direction of X-ray radiation striking the first detection region and the second detection region of the second detector, at least partially one is positioned behind the other.

[0009] Accordingly, the present invention proposes a modular DXR or IXR detection system having a first detector configured to be positioned adjacent to the object being scanned, and a second detector positioned at least partially behind the first detector and at least partially shielded from the object being scanned by the first detector. Both detectors detect X-ray radiation generated by a generator or source of an X-ray imaging system that passes through the object and strikes the detection system. The second detector can be repositioned relative to the first detector. Thus, a detector configuration having two at least partially overlapping detector layers is provided, where both detector layers detect signals used to form the final X-ray image, and the two detector layers can be repositioned relative to each other to adapt the detection area and / or characteristics of the detectors.

[0010] For example, in energy separation mode, a second detector, which may be smaller than the first detector, can be positioned in the region of interest to provide spectral imaging of the region of interest while the first detector acquires information for a whole-body image. Preferably, the first and second detectors may differ in pixel size, spatial resolution, and / or energy sensitivity, etc. Therefore, advantageously, if one detector is shielded from the object being scanned by the other detector, the detection areas of the two detectors, slid behind each other, are used for image reconstruction.

[0011] In one embodiment of the present invention, the first detection region and the second detection region are arranged essentially parallel or concentrically to each other. This is because radiation emitted from the X-ray source passes through both the first and second detection regions and is detected by both detectors. The detection regions may be planar or curved. In the case of curved surfaces, the detectors may be arranged concentrically.

[0012] In one embodiment of the present invention, the second detector is configured to move in parallel with respect to the first detector in a direction parallel to the surface of the first detection area of ​​the first detector and / or in a direction perpendicular to the surface of the first detection area of ​​the first detector. Optionally, at least one of the detectors may be a curved main detector, and the smaller detector may follow the curved shape of the main detector when moved. In this case, it may be necessary to tilt the smaller detector to adjust its alignment with the main detector.

[0013] In one embodiment of the present invention, the size of the second detection region of the second detector is different from the size of the first detection region of the first detector.

[0014] In one embodiment of the present invention, the spatial resolution of the second detector is different from the spatial resolution of the first detector.

[0015] In one embodiment of the present invention, the penetration of the first detector with respect to X-ray radiation impacting the first detection region and the second detection region is higher than the penetration of the second detector with respect to X-ray radiation impacting the first detection region and the second detection region.

[0016] In one embodiment of the present invention, the energy sensitivity of the second detector is different from that of the first detector. Therefore, the first and second detectors can preferably detect X-rays having different wavelengths.

[0017] In one embodiment of the present invention, the detection system further comprises a processing unit configured to reconstruct an X-ray image based on the X-ray radiation detected by the first detector and the second detector.

[0018] In one embodiment of the present invention, the reconstructed X-ray image has a first region and a second region, the first region being reconstructed based on X-ray radiation detected by both a first detector and a second detector, and the second region being reconstructed based on X-ray radiation detected by one of the first detector and the second detector, and at least one image characteristic of the X-ray image is better in the first region than in the second region. Therefore, the first region can enable spectral imaging, higher spatial resolution, higher image quality with less scattering, etc. Optionally, the precise positions of the first detector and / or the second detector can be measured, and the positional information can be used, for example, for image reconstruction, since the position may change over time.

[0019] In one embodiment of the present invention, at least one of the first detector and the second detector has a scattering prevention grid.

[0020] According to another aspect of the present invention, an X-ray imaging system having a detection system and an X-ray source according to any of the embodiments described above is provided.

[0021] In one embodiment of the present invention, the X-ray imaging system includes a beam collimator, which is configured to focus the X-ray radiation emitted from the X-ray source onto an area covered by a first detection area and a second detection area. Adaptation of the beam collimator with a beam tube collimator may be necessary to adapt the beam to the size of the detector and the area of ​​the body being imaged.

[0022] In one embodiment of the present invention, the X-ray imaging system further includes an irradiation indicator, which is configured to visualize an anatomical region of the object to be imaged, the anatomical region being positioned between the X-ray source and at least one of a first detection region and a second detection region. For example, a laser beam can be used to indicate the boundary of the detection region on the object.

[0023] In one embodiment of the present invention, the irradiation indicator is configured to separately visualize an anatomical region located between the X-ray source and a first detection region, and an anatomical region located between the X-ray source and a second detection region.

[0024] According to another aspect of the present invention, a method is provided for imaging an object using an X-ray imaging system according to any of the embodiments described above. This method comprises the steps of providing an X-ray imaging system, positioning an object between an X-ray source and a detection system, adjusting the position of at least one of the first and second detectors of the detection system, and acquiring an image of at least an anatomical region of the object. Preferably, the region of interest of the object is imaged with enhanced quality and / or different imaging characteristics. Therefore, the advantages provided by any of the above embodiments apply equally to all the other embodiments, and vice versa.

[0025] In summary, the present invention relates to a detection system for an X-ray imaging system. The detection system comprises a first detector and a second detector, each detector having a detector region and configured to detect X-ray radiation emitted by the X-ray source of the X-ray imaging system that strikes its respective detection region. The detection system is configured to adjust the position of at least one of the first detector and the second detector relative to the other of the first detector and the second detector. The first detection region of the first detector and the second detection region of the second detector can be positioned at least partially behind the other with respect to the direction of X-ray radiation emitted from the X-ray source of the X-ray imaging system.

[0026] One advantage of an embodiment of the present invention of a detection system having a flexible geometry is that the region of interest of a patient can be imaged with spectral X-ray imaging. Another advantage is that the field of view of the X-ray system, particularly the entire detection region, can be extended by using two partially overlapping detectors. Another advantage is that an adaptation of the spatial resolution of the detection system is applied, leading to a zoom function of the detection system. Another advantage is that when a second detector applies an anti-scatter grid, the scattered radiation generated by the first detector and reaching the second detector can be reduced.

[0027] These advantages are not limiting, and other advantages may be envisioned within the context of this application.

[0028] The above aspects and embodiments will become apparent from the exemplary embodiments described below and will be described with reference thereto. Exemplary embodiments of the present invention will be described below with reference to the following drawings.

Brief Description of the Drawings

[0029] [Figure 1A] Shows a schematic setup of a detection system for an X-ray imaging system according to an embodiment of the present invention. [Figure 1B] Shows a schematic setup of a detection system for an X-ray imaging system according to an embodiment of the present invention. [Figure 1C] Shows a schematic setup of a detection system for an X-ray imaging system according to an embodiment of the present invention. [Figure 2] Shows a schematic setup of an X-ray imaging system having a detection system according to an embodiment of the present invention. [Figure 3] Shows a block diagram of a method of imaging an object using an X-ray imaging device according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0030] Figures 1A to 1C show a schematic setup of the detection system 100 for the X-ray imaging system 200 according to an embodiment of the present invention. Different geometric relationships between the two detectors for the diagnostic X-ray imaging system are shown.

[0031] In the first exemplary embodiment shown in Figure 1A, a complete overlap is shown between the first detection region 111 of the first detector 110 and the second detection region 121 of the second detector 120. The detection regions of both detectors are positioned parallel to each other and are configured to detect X-ray radiation 220 emitted from the radiation source 210 of the X-ray imaging system 200. The X-ray radiation 220 passes through the first detection region 111 and the second detection region 121 and is detected by both detectors, which is made possible by at least a partial overlap of the respective detection regions 111, 121. The signals from both detectors are used to reconstruct an X-ray image. In this embodiment, at least the second detector 120 is configured so that its position relative to the first detector 110 can be adjusted. This repositioning is indicated by a double arrow lateral to the second detector, which indicates lateral movement in the xy direction parallel to the first detection region 111. This allows for the selection of a region of interest of the object 140 to be imaged, where an overlapping region is realized in which both detectors detect X-rays that pass through the overlapping region. Imaging outside the overlapping region is performed by a single detector, i.e., the first detector 110 in this embodiment.

[0032] In the second exemplary embodiment shown in Figure 1B, a configuration is shown in which there is only partial overlap between the first detection region 111 and the second detection region 121. Moving the second detector 120 to the boundary of the first detector 110 can result in this partial overlap. However, the X-ray emission 220 still penetrates at least partially through both the first detection region 111 and the second detection region 121. In this configuration, the full area of ​​the field in which X-rays can be detected in the X-ray imaging system can be extended. Furthermore, an overlapping region in which both detectors detect the X-ray emission 220 can be realized.

[0033] In a third exemplary embodiment shown in Figure 1C, a configuration of the detection system 100 is shown in which the distance in the z-direction between the first detector 110 and the second detector 120 can be further adjusted. Thus, movement of the detectors in the plane and perpendicular to the plane is possible. This may have the advantage that the second detector 120 detects less scattered radiation generated in the first detector 110. Specifically, after a certain distance, the amount of scattered radiation detected by the second detector 120 decreases, but direct, unscattered high-energy X-ray radiation still reaches the second detector 120.

[0034] It should be noted that the figure shows a situation where the first detector 110, in particular the first detection region 111, is larger than the second detection region 121 of the second detector 120. However, in other embodiments not shown, the second detector 120 may exceed the size of the first detector.

[0035] While there may be advantages to using two detectors with identical characteristics, the proposed concept can be further enhanced by implementing two detectors with different characteristics. Therefore, the following combinations are possible: - Transparency: When the two detectors overlap, the overlapping portion can be used for double detection of X-ray radiation 220 penetrating the overlapping portion. Therefore, it is advantageous if the first detector 110 has higher penetration to the applied radiation than the second detector 120. - Resolution: It may be advantageous if the first detector 110 has a different spatial resolution than the second detector 120. For example, the first detector 110 may be a smaller, higher-resolution detector, and the second detector 120 may be a larger, lower-resolution detector. In such a configuration, a higher-resolution image of the region of interest can be realized over a wider field of view with lower resolution. - Spectrum: It may be advantageous if the first detector 110 has different spectral characteristics from the spectrum of the second detector 120. For example, the first detector 110 may be sensitive to X-rays of a given first wavelength, and the second detector 120 may be sensitive to X-rays of a given second wavelength. With such a configuration, spectral imaging can be achieved. Preferably, the first detector 110 is more sensitive to long-wavelength, low-energy X-rays, and the second detector 120 is more sensitive to shorter-wavelength, high-energy X-rays.

[0036] In general, any combination of the different characteristics described above can be considered. For example, two detectors with different functions, such as spectral sensitivity and spatial resolution, as well as a dual detection function in overlapping regions, can be used. This can result in X-ray images that have high resolution at one wavelength and low resolution at the other.

[0037] Preferably, the first detection region 111 and the second detection region 121 are arranged essentially parallel or concentrically with respect to each other. This ensures that the radiation emitted from the X-ray source 210 passes through both the first detection region 111 and the second detection region 121 and is therefore detected by both detectors. The detection regions may be planar or curved. If planar, the detectors may be arranged parallel to each other, or at least essentially parallel. If curved, the detectors may be arranged concentrically.

[0038] Preferably, the second detector 120 is movable so that it can be moved relative to the first detector 110 in a direction parallel and / or perpendicular to the surface of the first detection 111 of the first detector 120. Optionally, at least one of the detectors may be a curved main detector, and the smaller detector may follow the curved geometric configuration of the main detector when moved. In this case, it may be necessary to tilt the smaller detector to adjust its alignment with the main detector.

[0039] In an embodiment of the present invention, the detection system 100 has a processing unit 130 that communicates with a first detector 110 and a second detector 120 and generates an X-ray image based on the X-ray emission 220 detected by the first detector 110 and the second detector 120.

[0040] Preferably, the generated or reconstructed X-ray image has a first region and a second region. The first region can be reconstructed based on X-ray emission 220 detected by both the first and second detectors, while the second region is reconstructed based on X-ray emission 220 detected by only one of the first or second detectors. Thus, the first region is an overlapping region of the first detection region 111 and the second detection region 121 such that at least one image characteristic of the X-ray image can be different in the first region from that of the second region, and preferably better in the first region than in the second region. Thus, the first region can enable at least one of spectral imaging, higher spatial resolution, higher image quality with less scattering, etc. Optionally, the precise positions of the first detector 110 and / or the second detector 120 can be measured, and since their positions may change over time with the X-ray scan, the positional information can be used, for example, for image reconstruction.

[0041] Furthermore, at least one of the detectors, preferably a second detector 120, may have a scattering prevention grid to suppress radiation scattered by the first detector 110.

[0042] Figure 2 shows a schematic setup of an X-ray imaging system 200 having a detection system 100 and an X-ray source 210 according to an embodiment of the present invention. The patient is positioned as the subject 140 to be imaged between the detection system 100 and the X-ray source 210 of the X-ray imaging system 200. X-ray radiation 220 emitted from the X-ray source 210 passes through the subject 140, as well as both the first detection area 111 of the first detector 110 and the second detection area 121 of the second detector 120. A processing unit 130 is used to read out the information received from the two detectors and to generate an X-ray image of the subject 140 using the data from both detectors.

[0043] Optionally, the X-ray imaging system 200 may have a beam collimator that focuses the X-ray radiation 220 emitted by the X-ray source 210 onto the area covered by the first detection area 111 and the second detection area 121. Adaptation of the beam collimator with a tube collimator may be necessary to adapt the beam to the detector size and the body area being imaged. Furthermore, an irradiation indicator may be used to visualize the anatomical area of ​​the object 140 being imaged. For example, a laser beam may be used to indicate the boundary of the detection area or the shape of the X-ray beam on the object 140. Preferably, the irradiation indicator can separately visualize the anatomical area located between the X-ray source 210 and the first detection area 111 and the anatomical area located between the X-ray source 210 and the second detection area 121.

[0044] Therefore, a collimator can be used to geometrically restrict the X-ray beam so that only the relevant anatomical region of the patient is illuminated. This is usually done by an optical system that illuminates the beam with visible light, allowing the operator to properly adjust the collimator. It is desirable to show the operator separately which regions are capable of spectral imaging and conventional imaging, using a detection system with two regions having different characteristics. Thus, one possible option may be to use a beam indicator that visualizes the position of the collimator blade of the beam collimator by four laser lines. In this case, the position of the detector edges of both detectors can be visualized by four additional laser lines, preferably using a different color from the first four laser lines.

[0045] Optionally, a second detector 120 can be positioned on the same arc at an angle of approximately 59° with respect to the central axis of the beam, and since the scattering peak is at the aforementioned angle, maximum scattering information can be obtained. A well-reconstructed volume from the second detector 120 can be used as a scattering mask, which can be applied to the primary volume acquired by the first detector 110 to remove scattering artifacts. The aforementioned positioning of the second detector 120 at an angle of 59° with respect to the central beam can also be used to complement the primary volume with scattering information.

[0046] Furthermore, even if the first detector 110 and the second detector 120 differ in pixel dimensions, or even if they have the same spatial resolution but are intentionally misaligned, the images corresponding to overlapping regions can be reconstructed at a higher resolution than either the first detector 110 or the second detector 120 could achieve using super-resolution techniques for image reconstruction.

[0047] Figure 3 shows a block diagram of a method for imaging a subject 140 using an X-ray imaging apparatus 200 according to an embodiment of the present invention. This method includes the steps of: providing the X-ray imaging apparatus 200 in step S110; positioning the subject 140 between the X-ray source 210 and the detection system 100 in step S120; adjusting the position of at least one of the first detector 110 and the second detector 120 of the detection system 100 in step S130; and acquiring an image of at least an anatomical region of the subject 140 in step S140. Therefore, preferably, the region of interest of the subject 140 is imaged with different imaging characteristics, such as enhanced quality and / or spectral imaging.

[0048] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustrations and descriptions should be considered illustrative or descriptive and not limiting. The present invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and achieved by those skilled in the art in carrying out the claimed invention, based on an examination of the drawings, disclosure and dependent claims.

[0049] In the claims, the word “having” does not preclude other elements or steps, and the indefinite article “a” or “an” does not preclude plurality. The mere fact that certain means are described in different dependent claims does not imply that combinations of these means cannot be used advantageously. No reference numeral in the claims should be construed as limiting in scope. [Explanation of Symbols]

[0050] 100 detection systems 110 First detector 111 First detection area 120 Second detector 121 Second detection area 130 processing units 140 targets 200 X-ray imaging system 210 X-ray source 220 X-ray radiation

Claims

1. In a detection system for an X-ray imaging system, the detection system is A first detector configured to detect X-ray radiation from the X-ray imaging system that collides with a first detection region, A second detector configured to detect X-ray radiation from the X-ray imaging system that collides with a second detection region, It has, The detection system is configured to adjust the position of at least one of the first detector and the second detector relative to the other of the first detector and the second detector. The detection system is configured such that the first detection region of the first detector and the second detection region of the second detector are positioned, at least partially, behind the other with respect to the direction of the X-ray emission that strikes the first and second detection regions. The size of the second detection region of the second detector is different from the size of the first detection region of the first detector. The detection system further comprises a processing unit configured to reconstruct an X-ray image based on the X-ray radiation detected by the first detector and the second detector. The reconstructed X-ray image has a first region and a second region, the first region is reconstructed based on X-ray radiation detected by both the first and second detectors, and the second region is reconstructed based on X-ray radiation detected by either the first or second detector, and at least one image characteristic of the X-ray image is better in the first region than in the second region. Detection system.

2. The detection system according to claim 1, wherein the first detection region and the second detection region are arranged essentially parallel or concentrically with respect to each other.

3. The detection system according to claim 1 or 2, wherein the second detector is configured to move relative to the first detector in a direction parallel to the surface of the first detection area of ​​the first detector, and / or in a direction perpendicular to the surface of the first detection area of ​​the first detector.

4. The detection system according to any one of claims 1 to 3, wherein the spatial resolution of the second detector is different from the spatial resolution of the first detector.

5. The detection system according to any one of claims 1 to 4, wherein the penetration of the first detector to the X-ray radiation impacting the first detection region and the second detection region is higher than the penetration of the second detector to the X-ray radiation impacting the first detection region and the second detection region.

6. The detection system according to any one of claims 1 to 5, wherein the energy sensitivity of the first detector is different from the energy sensitivity of the second detector.

7. The detection system according to any one of claims 1 to 6, wherein at least one of the first detector and the second detector has a scattering prevention grid.

8. An X-ray imaging system comprising a detection system according to any one of claims 1 to 7 and an X-ray source.

9. The X-ray imaging system according to claim 8, further comprising a beam collimator, the beam collimator configured to focus the X-ray radiation emitted by the X-ray source into an area covered by the first detection region and the second detection region.

10. The X-ray imaging system according to any one of claims 8 or 9, further comprising an irradiation indicator configured to visualize an anatomical region of an object to be imaged, wherein the anatomical region is located between the X-ray source and at least one of the first detection region and the second detection region.

11. The X-ray imaging system according to claim 10, wherein the irradiation indicator is configured to separately visualize the anatomical region of the target located between the X-ray source and the first detection region, and the anatomical region of the target located between the X-ray source and the second detection region.

12. A method for imaging an object using an X-ray imaging system according to any one of claims 8 to 11, The steps include providing the aforementioned X-ray imaging system, The steps include: positioning the object between the X-ray source and the detection system; A step of adjusting the position of at least one of the first detector and the second detector of the detection system, The steps include: obtaining an image of at least an anatomical region of the subject; A method having.

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