CN115061183A - Laminated scintillator structure for realizing X-ray multi-energy spectrum imaging and imaging equipment - Google Patents

Abstract

The invention discloses a laminated scintillator structure for realizing X-ray multi-energy spectrum imaging and imaging equipment, and belongs to the technical field of X-ray detection and imaging. The invention stacks scintillators with different X-ray absorption coefficients and different scintillation light wave bands through a special arrangement sequence to form a multilayer composite structure, the top layer scintillator is mainly responsible for absorbing low-energy X-rays and emitting scintillation light of the longest wave band, the next layer mainly absorbs X photons of the next highest energy wave band and emits photons of the next shortest wave band, and so on, and the scintillator of the bottommost layer absorbs the X-rays with the highest energy and generates the scintillation photons with the shortest wave band. The invention can finish the reading of X-ray spectral information and the imaging of the spatial position by one-time X-ray irradiation, thereby greatly improving the imaging speed and reducing the dosage of rays required by imaging; the accumulation effect which is the inherent defect of the existing energy resolution detector is avoided, and the detector can be normally used under high-flux X-rays; moreover, the method can be well compatible with the mature silicon-based detection technology, such as CMOS based on crystalline silicon and TFT array based on amorphous silicon.

Description

A layered scintillator structure and imaging device for realizing X-ray multi-energy spectral imaging

technical field

The invention belongs to the technical field of X-ray detection and imaging, and provides a layered scintillator structure and an imaging device capable of realizing large-area X-ray multi-energy spectrum imaging at low cost.

Background technique

The widely used X-ray imaging technique creates image contrast by measuring the total X-ray dose penetrating an object, making it almost indistinguishable for materials with similar atomic numbers or densities. In the energy range of 0-200keV, the effect of X-rays on matter is mainly determined by the photoelectric effect and Compton scattering, both of which are closely related to the energy of X-ray photons. Strong energy dependency. In this case, spectral resolution can add "color" information to the X-ray image, which can help us see information that cannot be seen in energy-integrating X-ray grayscale imaging.

By detecting the attenuation of different energy components in X-rays, energy-resolved X-ray imaging enables more precise detection of substances and produces better image contrast. The mainstream technology of energy-resolved detection currently relies on photon counting. Although this technology is currently in clinical trials in high-end equipment such as scanning CT, it still has many shortcomings that limit its wide application in more X-ray imaging equipment. . First, it is very difficult to grow high-quality CZT single crystals. At present, the high-quality CZT single crystals that can be used for energy spectral CT are only mastered by very few companies; In addition, the size of the CZT single crystal is very small, and each CZT detector unit requires a complex circuit system, so its pixel integration is very low, far from impossible Compared with the high-pixel silicon-based detection technology, it is impossible to obtain a large area array X-ray imaging at one time under the condition of a single X-ray exposure, and can only be imaged by scanning, which greatly increases the imaging time and imaging requirements. dose. This type of energy spectrum imaging technology based on the principle of photon counting is difficult to directly apply to the widely used large-area flat-panel X-ray imaging field. At present, there are no FPXI devices and technologies that can realize hyperspectral and large area arrays on the market.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a layered scintillator structure and imaging equipment for realizing X-ray multi-spectral imaging in view of the above-mentioned technical problem of lack of effective and simple production cost of large-area array X-ray multi-spectrum imaging.

The concrete technical scheme adopted in the present invention is as follows:

In a first aspect, the present invention provides a layered scintillator structure for realizing X-ray multi-energy spectrum imaging, which is formed by superimposing N layers of scintillators, N≥2, wherein different layers of scintillators have different X-ray absorption capabilities, Each layer of scintillator corresponds to one main absorption energy segment; the energy spectrum of the X-ray source adapted to the stacked scintillator structure is equally divided into N energy segments, and the N layers of scintillators are directed from the X-ray incident side toward the The main absorption energy segment of the n-th layer of scintillators sequentially counted on the exit side is the n-th energy segment sequentially counted from low to high energy in the energy spectrum, and the absorption energy of each layer of scintillator to its main absorption energy segment accounts for This layer of scintillator absorbs more than 50% of the total X-ray energy; among the N layers of scintillators, the center wavelength of the scintillation light emitted by each layer of scintillator along the X-ray incident side toward the output side decreases monotonically layer by layer, and any two The overlapping area of the scintillation light spectrum emitted by the layer scintillator should meet the requirement of discrimination when imaging in the same imaging device.

As a preference of the above-mentioned first aspect, the materials of the N-layer scintillators are different, and each layer of scintillator can adjust the absorption rate for different energy segments by optimizing the thickness of the material layer.

As a further preference of the above-mentioned first aspect, when optimizing the material layer thickness of each layer of scintillator, the thickness of the first layer to the Nth layer of scintillator is calculated in the order from the X-ray incident side to the exit side; When the thickness of the n-th layer of scintillator is arbitrary, using Lambert Beer's law and the absorption coefficient curve of the n-th layer of scintillator material to X-rays with different energies, calculate the absorption of the n-th layer of scintillator to the n-th energy range of X-rays The energy accounts for more than 50% of the total X-ray absorption energy of the scintillator.

As a further preference of the above-mentioned first aspect, the N is preferably 2-5.

As a preference of the above-mentioned first aspect, the ratio of the overlapping area of the scintillation light spectra emitted by any two layers of scintillators to the respective scintillation light spectral areas should be less than 20%.

As a further preference of any one of the above-mentioned first aspect, the N=2, counting sequentially from the X-ray incident side to the output side, the material of the first layer of scintillator is C ₄ H ₁₂ NMnCl ₃ , and the corresponding main absorption energy The segment is 0-30keV, the corresponding scintillation light is red light, the second layer of scintillator material is Cs ₃ Cu ₂ I ₅ , the corresponding main absorption energy segment is 30-60 keV, and the corresponding scintillation light is blue light.

As a further preference of any one of the above-mentioned first aspect, the N=3, counting sequentially from the X-ray incident side to the output side, the material of the first layer of scintillator is C ₄ H ₁₂ NMnCl ₃ , and the corresponding main absorption energy The second layer of scintillator material is (C ₈ H ₂₀ N) ₂ MnBr ₄ , the corresponding main absorption energy range is 20 to 40 keV, and the corresponding scintillation light is For green light, the scintillator material of the third layer is Cs ₃ Cu ₂ I ₅ , the corresponding main absorption energy range is 40-60 keV, and the corresponding emitted scintillation light is blue light.

As a further preference of any one of the above-mentioned first aspect, the N=4, counting sequentially from the X-ray incident side to the exit side, the material of the first layer of scintillator is FAPbI ₃ , and the corresponding main absorption energy range is 0～ 15keV, the corresponding scintillation light is near-infrared light, the second layer of scintillator material is C ₄ H ₁₂ NMnCl ₃ , the corresponding main absorption energy range is 15 ~ 30keV, the corresponding scintillation light is red light, the third layer scintillation The bulk material is (C ₈ H ₂₀ N) ₂ MnBr ₄ , the corresponding main absorption energy range is 30-45 keV, and the corresponding scintillation light is green light. The fourth layer of scintillator material is Cs ₃ Cu ₂ I ₅ , corresponding to The main absorption energy range is 45-60keV, and the corresponding flashing light is blue light.

In a second aspect, the present invention provides an X-ray multi-energy spectrum imaging device, including an X-ray source, a scintillator module, and a spectral imaging module, wherein the scintillator module adopts the laminated scintillation according to any solution of the first aspect The spectral imaging module is disposed directly behind the X-ray emission direction of the stacked scintillator structure, and is used to simultaneously record the scintillation light of different wavelengths emitted by each layer of scintillator.

As a preferred option of the second aspect, the spectral imaging module is a silicon-based multispectral camera or a hyperspectral camera.

Compared with the prior art, the present invention has the following beneficial effects:

The invention adopts the composite structure of superimposed multi-layer scintillators to realize X-ray multi-energy spectrum imaging, and has the advantages of cost and simple process. The X-ray multi-spectrum imaging device constructed based on the laminated scintillator structure in the present invention can complete the reading of X-ray spectral information and the imaging of the spatial position through one X-ray irradiation, which greatly improves the imaging speed and reduces the imaging cost. radiation dose required. The invention avoids the inherent defect "stacking effect" of the existing energy-resolving detectors, can be used normally under high-flux X-rays, and can be well compatible with the current mature silicon-based detection technology.

Description of drawings

FIG. 1 is a scintillation light spectrum diagram of each layer of a double-layer scintillator.

FIG. 2 is a graph showing the absorption of X-rays of different energies by the upper and lower layers of the double-layer scintillator.

FIG. 3 is a schematic diagram and an imaging effect diagram of a double-layer scintillator structure.

FIG. 4 is a scintillation light spectrum diagram of each layer of the three-layer scintillator.

FIG. 5 is a schematic diagram and an imaging effect diagram of a three-layer scintillator structure.

FIG. 6 is a scintillation light spectrum diagram of each layer of the four-layer scintillator.

FIG. 7 is a schematic diagram and an imaging effect diagram of a four-layer scintillator structure.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined correspondingly on the premise that there is no conflict with each other.

As a preferred implementation form of the present invention, a layered scintillator structure for realizing X-ray multi-energy spectrum imaging is provided, and the layered scintillator structure is formed by superimposing N layers of scintillators, N≥2. The specific number of scintillator layers can be optimized according to the actual situation. Considering the limitation of actual material selection and the requirements of application scenarios, N is generally preferably 2-5. In the layered scintillator structure, different layers of scintillators have different X-ray absorption capabilities, and each layer of scintillators corresponds to a main absorption energy segment. In the present invention, the definition of the main absorption energy segment is as follows: each layered scintillator structure has its own energy spectrum of the X-ray source suitable for it, and the energy spectrum of the X-ray source suitable for the layered scintillator structure is divided into equal parts. N energy segments, then in the N layers of scintillators, the main absorption energy segment of the n-th layer of scintillators sequentially counted from the X-ray incident side to the X-ray output side is the nth energy in the above energy spectrum counted from low to high energy in sequence That is to say, the N energy segments formed by dividing the energy spectrum of the X-ray source into equal parts are sequentially used as the main absorption energy segments of the N-layer scintillator. From low to high, they are recorded as I(1) to I(N), and the layers of scintillators from the X-ray incident side to the output side are recorded as the first layer to the Nth layer in order. Then the main scintillator of the nth layer is The absorbed energy segment is I(n). It should be noted that the main absorption energy section has requirements for the absorption rate of the corresponding energy section. Specifically, the absorption energy of each layer of scintillator to its main absorption energy section accounts for the total absorption of X-rays by this layer of scintillators. more than 50% of the energy. In addition, among the N layers of scintillators, the center wavelength of the scintillation light emitted by each layer of scintillator along the X-ray incident side toward the output side decreases monotonically layer by layer, and the overlapping area of the scintillation light spectrum emitted by any two layers of scintillators should satisfy the same requirement. Discrimination requirements for imaging in imaging equipment.

It should be noted that the so-called "meeting the requirements for the degree of discrimination when imaging in the same imaging device" in the present invention means that when different spectra are imaged in the same multispectral or hyperspectral imaging device, sufficient differentiation should be maintained. degree, enabling the extraction of corresponding spectral information from the final imaging data. Preferably, if the central wavelengths of the scintillation light emitted by the scintillators from the first layer to the n-th layer are denoted as R(1)~R(N), then R(1)~R(N) not only satisfy the requirement of monotonically decreasing , the proportion of the overlapping area of the scintillation light spectra emitted by any two layers of scintillators in the respective scintillation light spectral areas should be less than 20%. For example, the scintillation light spectrum of one layer of scintillator is A, the scintillation light spectrum of another layer of scintillator is B, and the overlapping area of A and B is denoted as A∩B, then A∩B in A and B The proportion cannot exceed 20%, so as to ensure that the information of A and B can be extracted from the imaging data after the final simultaneous imaging.

The above-mentioned laminated scintillator structure in the present invention can be used to construct an X-ray multi-energy spectrum imaging device, such an imaging device includes an X-ray source, a scintillator module, and a spectral imaging module, wherein the scintillator module adopts the laminated scintillator of the present invention structure, and the spectral imaging module is disposed directly behind the X-ray emission direction of the stacked scintillator structure, and is used to simultaneously record the scintillation light of different wavelengths emitted by each layer of scintillator. Further, the spectral imaging module can use a silicon-based multispectral camera or a hyperspectral camera.

The above-mentioned laminated scintillator structure for realizing X-ray multi-energy spectral imaging and the corresponding X-ray multi-energy spectral imaging device of the present invention can realize low-cost and large-area X-ray multi-energy spectral imaging. The reason is that different scintillators Due to the different main absorption energy segments and the monotonically decreasing central wavelength of the scintillation light in the layer body, the scintillation light of different wavelengths can be simultaneously imaged by a multispectral camera or a hyperspectral camera directly behind the X-ray emission direction. Such a stacked scintillator structure can obtain large-area array X-ray imaging data at one time under the condition of a single X-ray exposure, and the scintillation light intensities of different wavelengths in the imaging data can be well inverted and extracted. Compared with the traditional method in which the imaging method can only be continuously scanned, the present invention greatly reduces the imaging time and the dose required for imaging.

It should be noted that the main absorption energy range of the above scintillators of different layers needs to be changed by material selection and material layer thickness, while the central wavelength of the scintillation light of the scintillator is mainly determined by the material selection. Therefore, in order to meet the functional requirements of the stacked scintillator structure in the present invention, it is preferable to set the N layers of scintillators with different materials, and each layer of scintillator can adjust the absorption rate of different energy bands by optimizing the thickness of the material layer. In the present invention, each layer of scintillator mainly absorbs X-rays in a certain energy range by selecting appropriate materials and designing appropriate thicknesses. In the calculation of the thickness, it is preferable to use the absorption coefficient curve of the material for different energy X-rays, and substitute the central energy of the corresponding energy interval as a representative into Lambert Beer's law for calculation, so that the layer of scintillator mainly absorbs X-rays of this energy and Rarely absorbs rays in other energy ranges.

Further, when optimizing the material layer thickness of each layer of scintillator, the thickness of the first layer to the Nth layer of scintillator can be calculated in the order from the X-ray incident side to the output side; wherein, the calculation of any nth layer scintillator Using Lambert Beer's law and the absorption coefficient curve of the n-th layer of scintillator material to X-rays with different energies, it is calculated that the absorption energy of the n-th layer of scintillators to the n-th energy range of X-rays accounts for the scintillation of this layer. The body absorbs more than 50% of the total energy of X-rays.

In a preferred embodiment of the present invention, the above-mentioned laminated scintillator structure and the large-area array X-ray multi-energy spectrum imaging device can be specifically designed according to the following operation steps:

(1) Selection of materials for each layer in the multilayer scintillator structure

a. In the multi-layer scintillator structure, each layer of material has different X-ray absorption ability. Specifically, the top layer material has the worst X-ray absorption ability, and the next layer material has better X-ray absorption ability than the previous layer. By analogy, the bottom scintillator material has the strongest ability to absorb X-rays. When selecting the materials of each layer, the top layer can be selected from organic materials or materials composed of elements with a small atomic number. The content of heavy elements in the material increases with The layers are gradually increased, and the material with the highest content of heavy elements is selected for the bottom layer; b. In the multi-layer scintillator structure, the emission wavelength of each layer of material under X-rays is different, specifically, the scintillation light emitted from the top layer to the bottom layer The center wavelength gradually decreases monotonically, and the overlapping area of each scintillation light spectrum is less than 20%; for example, the top layer material emits the longest wavelength band of scintillation light (such as near-infrared light), and the next layer material emits a slightly shorter wavelength than the previous layer. Scintillation light (such as yellow light), and so on, the bottom material emits scintillation light with the shortest wavelength (such as blue light); therefore, when selecting each layer of material to construct a multi-layer scintillator structure, these two requirements should be taken into account.

(2) Design of the thickness of each layer in the multilayer scintillator structure

According to the number N of layers in the multi-layer scintillator structure, the emission energy spectrum of the X-ray source can be divided into several energy segments equal to the number of layers at equal distances, which are respectively used as the main absorption energy segments of the N-layer scintillator. And in order to make each layer of scintillator absorb more than 50% of the X-ray energy in the energy range corresponding to the number of layers, it is necessary to calculate the appropriate thickness of each layer of material to meet this requirement. Starting from the top scintillator material, use Lambert Beer's law and the material's absorption coefficient curve for X-rays of different energies to calculate the appropriate thickness, so that the proportion of the layer of scintillator absorbing the X-rays in the first energy segment exceeds the total amount of the layer. 50% of the absorption; similarly, for the second layer of scintillator material, use Lambert Beer's law and the material's absorption coefficient curve for X-rays of different energies to calculate the appropriate thickness to make this layer of scintillator absorb the second energy The proportion of segment X-rays exceeds 50% of the total absorption of the layer; and so on, until the bottom scintillator material is calculated to have an appropriate thickness so that the proportion of X-rays that absorb the last energy segment exceeds 50% of the total absorption of the layer.

In order to simplify the equation, the central energy of each energy segment is generally used as a representative to substitute into Lambert Beer's law for calculation.

(3) Realization of large area array X-ray multi-spectral imaging equipment

The designed multi-layer scintillator structure is placed in the X-ray imaging system, and a silicon-based multi-spectral-hyperspectral camera is arranged behind the multi-layer scintillator. Under one X-ray exposure, each layer of the multi-layer scintillator structure absorbs differently. The energy rays emit scintillation light. Due to the different emission wavelengths, the scintillation images of different layers of scintillators can be obtained simultaneously with multi-spectral/hyperspectral cameras, which represent the imaging information of X-rays in different energy ranges, and can be matched with certain Spectral calculation method to achieve higher precision multi-spectral imaging.

To sum up, the present invention stacks scintillators with different X-ray absorption coefficients and different scintillation emission bands through a special arrangement sequence to form a multi-layer composite structure. The top scintillator is mainly responsible for absorbing low-energy X-rays and emitting scintillation light with the longest wavelength band. The next layer mainly absorbs X-rays in the next-highest energy band and emits photons in the next-shortest wavelength, and so on. The invention can complete the reading of X-ray spectral information and the imaging of the spatial position through one X-ray irradiation, which greatly improves the imaging speed and reduces the radiation dose required for imaging; effect”, which can be used normally under high-throughput X-rays; and our proposed method is well compatible with currently mature silicon-based detection technologies, such as crystalline silicon-based CMOS and amorphous silicon-based TFT arrays.

The following examples further describe and demonstrate preferred embodiments within the scope of the present invention. However, it should be noted that the given examples are only illustrative and should not be construed as limiting the present invention.

Example 1

This embodiment provides a double-layer scintillator structure for realizing X-ray multi-spectrum imaging, and the specific method is as follows:

1) Choose two different materials as the upper layer and the lower layer scintillator respectively. The upper layer material has a high content of elements with a small atomic number and has poor X-ray absorption ability, and the lower layer material has a high content of elements with a large atomic number and a strong X-ray absorption ability; And the scintillation light of the upper material has a long wavelength (such as red light), and the scintillation light of the lower material has a short wavelength (such as blue light);

2) Calculate the appropriate thickness of the upper and lower layers according to the material selected in the previous step, the upper layer material C ₄ H ₁₂ NMnCl ₃ (poor X-ray absorption ability, the scintillation light is red light), the lower layer material Cs ₃ Cu ₂ I ₅ (to The X-ray absorption ability is strong, and the scintillation light is blue light) as an example; the scintillation light spectrum of the two is shown in Figure 1, the central wavelengths are 646nm and 452nm respectively, and the spectral overlap area of the two is far less than 20%; according to the two The absorption coefficient curve and Lambert Beer's law of the material for X-rays of different energies, when the thickness of the upper and lower layers is 84um and 12um, respectively, the absorption of X-ray energy when the two are superimposed, as shown in Figure 2, can be It can be seen that the absorption of low-energy rays of 0-30keV by the upper layer accounts for about 80% of the total energy absorbed by the layer, and the absorption of high-energy rays of 30-60keV by the lower layer accounts for about 60% of the total energy absorbed by the layer.

4) Place the designed double-layer scintillator structure in the X-ray imaging system, perform X-ray imaging on the "skeletal-muscle" model, use a color camera to capture the luminescence image of the double-layer scintillator, and collect the RGB The image is divided into R and B channels, which are the luminescence images of two different luminescent color scintillators, as shown in Figure 3; the red image represents the low-energy X-ray imaging information, and the blue image represents the high-energy X-ray imaging information.

Example 2

This embodiment provides a three-layer scintillator structure for realizing X-ray multi-spectral imaging, and the specific method is as follows:

1) Choose three different materials as the upper, middle and lower scintillators respectively. The upper material has a high content of elements with a small atomic number and has poor X-ray absorption. The middle material has a small atomic number and a large atomic number. In part, the X-ray absorption ability is average, the lower layer material has a high content of elements with a large atomic number, and the X-ray absorption ability is strong; and the scintillation light wavelength of the upper layer material is long (such as red light), and the scintillation light wavelength of the middle layer material is shorter (such as Green light) the scintillation light of the underlying material has the shortest wavelength (such as blue light);

2) Calculate the appropriate thickness of the upper, middle and lower layers according to the material selected in the previous step, the upper layer material C ₄ H ₁₂ NMnCl ₃ (poor X-ray absorption ability, the scintillation light is red light), the middle layer material (C ₈ H ₂₀ N ) ₂ MnBr ₄ (the ability to absorb X-rays is average, the scintillation light is green light), and the underlying material Cs ₃ Cu ₂ I ₅ (the ability to absorb X-rays is strong, the scintillation light is blue light) as an example; the scintillation light spectrum of each layer is shown in the figure 4, the central wavelengths are 646nm, 521nm and 452nm respectively, and the spectral overlap area between the three is less than 20%; according to the absorption coefficient curves of the three materials for different energy X-rays and Lambert Beer's law, the When the thickness of the middle and lower layers is 100um, 200um and 50um respectively, the absorption of X-ray energy when the three are superimposed, the upper layer is for low-energy rays of 0-20keV, the middle layer is for medium-energy rays of 20-40keV, and the lower layer is for The absorption of high-energy rays from 40 to 60 keV accounts for more than 50% of the total energy absorbed by the layer;

4) Place the designed three-layer scintillator structure in the X-ray imaging system, perform X-ray imaging on the "skeletal-muscle" model, use a color camera to capture the luminescence image of the three-layer scintillator, and collect the RGB The image is divided into R, G and B channels, which are the luminescence images of scintillators with three different luminescence colors, as shown in Figure 5; the red image represents the low-energy X-ray imaging information, the green image represents the medium-energy X-ray imaging information, The blue image represents high-energy X-ray imaging information.

Example 3

This embodiment provides a four-layer scintillator structure for realizing X-ray multi-spectrum imaging, and the specific methods are as follows:

1) Four different materials were selected as the first, second, third and fourth layers of scintillators. The uppermost layer of the material had a high content of elements with a small atomic number, and had poor ability to absorb X-rays. The second layer of the material had a small atomic number of elements and Elements with large atomic numbers each occupy a part, and their ability to absorb X-rays is average. The third layer of materials has a large proportion of elements with large atomic numbers, and has better X-ray absorption ability. The ray absorption ability is strong; and the scintillation light wavelength of the upper layer material is the longest (such as near-infrared light), the scintillation light wavelength of the second layer material is relatively long (such as red light), and the scintillation light wavelength of the third layer material is shorter (such as green light). light), the scintillation light of the underlying material has the shortest wavelength (such as blue light);

3) Calculate the appropriate thickness of each layer of the four-layer scintillator according to the material selected in the previous step, the upper layer material FAPbI ₃ (scintillation light is near-infrared light), the second layer material C ₄ H ₁₂ NMnCl ₃ (poor X-ray absorption ability) , the scintillation light is red light), the third layer material (C ₈ H ₂₀ N) ₂ MnBr ₄ (the ability to absorb X-rays is average, the scintillation light is green light), the lower layer material Cs ₃ Cu ₂ I ₅ (the absorption of X-rays is green) The scintillation light spectrum of each layer is shown in Figure 6, the central wavelengths are 854nm, 646nm, 521nm and 452nm respectively, and the spectral overlap area between each layer is less than 20%; according to The absorption coefficient curves of the four materials for different energy X-rays and Lambert Beer's law, it is calculated that when the thickness of the four layers is 5um, 300um, 400um and 50um, the first layer is 0~15keV low energy rays, the second layer For medium-energy rays of 15-30 keV, the third layer absorbs 30-45 keV sub-high-energy rays, and the fourth layer absorbs 45-60 keV high-energy rays, respectively, accounting for more than 50% of the total energy absorbed by the layer; 4) The system A good four-layer scintillator structure is placed in the X-ray imaging system, X-ray imaging is performed on the "skeletal-muscle" model, and the luminescence image of the three layers after the four-layer scintillator is captured by a color camera, and the collected RGB image Separate the R, G and B channels, which are the luminous images of the scintillators with three different luminescent colors of red, green and blue. The scintillator image of the first layer is captured by an infrared camera. Putting these four images together is shown in Figure 7. They represent the imaging information of X-rays in four different energy regions, respectively.

The above-mentioned embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. Various changes and modifications can also be made by those of ordinary skill in the relevant technical field without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims (10)

1. A laminated scintillator structure for realizing X-ray multi-energy spectrum imaging is formed by superposing N layers of scintillators, wherein N is more than or equal to 2, the scintillators in different layers have different absorption capacities on X-rays, and each layer of scintillator corresponds to a main absorption energy section; the energy spectrum of an X-ray source matched with the laminated scintillator structure is equally divided into N energy sections, the main absorption energy section of the N-th layer of scintillators counted from the X-ray incidence side to the emergence side in the N layers of scintillators is the nth energy section counted from low energy to high energy in the energy spectrum, and the absorption energy of each layer of scintillators to the main absorption energy section accounts for more than 50% of the total absorption energy of the layer of scintillators to the X-rays; in the N layers of scintillators, the central wavelengths of the scintillation light emitted by each layer of scintillator facing the emergent side along the X-ray incident side are monotonically decreased layer by layer, and the overlapping areas of the spectra of the scintillation light emitted by any two layers of scintillators meet the requirement of discrimination during imaging in the same imaging device.

2. The stacked scintillator structure for X-ray multi-energy spectrum imaging as claimed in claim 1, wherein the N layers of scintillators are made of different materials, and the respective layers of scintillators are adjusted in absorption rate for different energy bands by optimizing the thickness of the material layer.

3. The stacked scintillator structure for realizing X-ray multi-energy spectrum imaging as claimed in claim 2, wherein when the thickness of the material layer of each layer of scintillator is optimized, the thickness calculation is performed on the scintillators of the 1 st layer to the Nth layer in sequence from the X-ray incidence side to the emission side; when the thickness of any nth layer of scintillator is calculated, the absorption energy of the nth layer of scintillator to the nth energy band X-ray is calculated to be more than 50% of the total absorption energy of the layer of scintillator to the X-ray by utilizing the Lambert beer law and the absorption coefficient curve of the nth layer of scintillator material to the X-ray with different energy.

4. The stacked scintillator structure for X-ray multi-energy spectrum imaging as claimed in claim 2, wherein N is preferably 2 to 5.

5. The stacked scintillator structure for X-ray multi-energy spectrum imaging as claimed in claim 1, wherein the ratio of the overlapping area of the spectra of the scintillations emitted from any two layers of scintillators in the respective spectra of scintillations is less than 20%.

6. The stacked scintillator structure for realizing X-ray multi-energy spectrum imaging as claimed in any one of claims 1 to 5, wherein said N-2 is counted in order from the X-ray incident side to the X-ray emergent side, and the material of the scintillator of layer 1 is C ₄ H ₁₂ NMnCl ₃ The corresponding main absorption energy section is 0-30 keV, the corresponding emitted scintillation light is red light, and the 2 nd layer scintillator material is Cs ₃ Cu ₂ I ₅ The corresponding main absorption energy section is 30-60 keV, and the corresponding emitted scintillation light is blue light.

7. The stacked scintillator structure for realizing X-ray multi-energy spectrum imaging as claimed in any one of claims 1 to 5, wherein N is 3, counted from the X-ray incidence side to the emission side, and the material of the 1 st layer scintillator is C ₄ H ₁₂ NMnCl ₃ The corresponding main absorption energy section is 0-20 keV, the corresponding emitted scintillation light is red light, the 2 nd layer scintillationThe scintillator material is (C) ₈ H ₂₀ N) ₂ MnBr ₄ The corresponding main absorption energy section is 20-40 keV, the corresponding emitted scintillation light is green light, and the 3 rd layer scintillator material is Cs ₃ Cu ₂ I ₅ The corresponding main absorption energy range is 40-60 keV, and the corresponding emitted scintillation light is blue light.

8. The stacked scintillator structure for realizing X-ray multi-energy spectrum imaging as claimed in any one of claims 1 to 5, wherein said N-4 counts sequentially from the X-ray incident side to the exit side, and the material of the scintillator of layer 1 is FAPbI ₃ The corresponding main absorption energy range is 0-15 keV, the corresponding emitted scintillation light is near infrared light, and the 2 nd layer scintillator material is C ₄ H ₁₂ NMnCl ₃ The corresponding main absorption energy range is 15-30 keV, the corresponding emitted scintillation light is red light, and the 3 rd layer scintillator material is (C) ₈ H ₂₀ N) ₂ MnBr ₄ The corresponding main absorption energy section is 30-45 keV, the corresponding emitted scintillation light is green light, and the 4 th layer of scintillator material is Cs ₃ Cu ₂ I ₅ The corresponding main absorption energy section is 45-60 keV, and the corresponding emitted scintillation light is blue light.

9. An X-ray multi-energy spectrum imaging device comprises an X-ray source, a scintillator module and a spectrum imaging module, and is characterized in that the scintillator module adopts a laminated scintillator structure according to any one of claims 1 to 8, and the spectrum imaging module is arranged right behind the X-ray emergent direction of the laminated scintillator structure and used for recording scintillation light with different wavelengths emitted by each layer of scintillator.

10. The X-ray multi-energy spectral imaging device of claim 9, wherein the spectral imaging module is a silicon-based multi-spectral camera or a hyper-spectral camera.

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