CN111388001A

CN111388001A - Non-rotating computed tomography imaging device and method

Info

Publication number: CN111388001A
Application number: CN202010248259.3A
Authority: CN
Inventors: 王振
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2020-07-10

Abstract

The invention discloses a non-rotary computed tomography device and a non-rotary computed tomography method. The detector is divided into three sections along the advancing direction of the detected object, a central part and two side parts, and the central part is a single-layer single-energy detector. In the imaging method, at least one ray source works at the same time, and the ray sources are rapidly switched. In the imaging process, the ray source limits the beam range, so that rays only pass through the central part of the annular detector close to one side of the ray source emitting the rays, and the detector on the other side of the annular detector receives the rays to realize signal acquisition. The imaging method further comprises a projection data processing method, wherein beam hardening correction is respectively carried out on signals of the detector at the central part and the detector at the two side parts, and the signals are unified to the same ray energy. The scheme of the invention can obviously improve the quality of computed tomography.

Description

Non-rotating computed tomography imaging device and method

Technical Field

The invention belongs to the field of Computed Tomography (CT) scanners, and particularly relates to a non-rotating CT imaging device and method. Can be used in the fields of medicine, security inspection and industrial detection.

Background

The CT equipment is widely applied in the fields of medicine, security inspection and industry. In the fields of medical and security applications, the mainstream scanning mode is still the rotary scanning of the radiation source and the detector rotating around the detected object. Medical CT devices have historically appeared in the so-called "fifth generation CT," which is the electron beam scanning CT (E-beam CT) from GE corporation, which employs a large scanning electron beam tube to simulate the rapid rotational movement of the radiation source focus by the rapid deflection of the electron beam, and can complete CT scanning without the rotation of the radiation source and the detector. But the device is not used in a large range due to the high cost, large volume and difficult whole body scanning of human body.

At present, the scanning speed of the medical CT equipment reaches 4r/s, the rotating speed of the Siemens double-source CT is 0.27r/s, and the rotating speed is equivalent to that of the single-source CT which needs 0.135s for one circle, so that the time resolution of the medical CT imaging is greatly improved. Even so, in order to realize cardiac scanning 4D-CT imaging, the time resolution still needs to be improved, and currently, cardiac imaging usually needs to be assisted by an electrocardiographic gating technique, so as to complete CT fast scanning at the end diastole and the end systole of the heart, and for equipment with lower time resolution, even multi-sector reconstruction is needed. However, since the rotational speed of mechanical systems has almost reached its limit, the space for improving the temporal resolution of CT using rotational scanning has been very limited. There is no non-rotating static CT after the E-beam CT of GE to enter the medical imaging equipment market. Patent CN101512379A provides an imaging geometry comprising a plurality of addressable sources and their corresponding circular or semi-circular detectors, with gaps between the circular or semi-circular detectors, where the sources are arranged. The structure either needs a plurality of groups of structure combinations, or a detector does not exist at the position opposite to the ray source, the former can lengthen the length of the device, and the latter has data loss, thereby reducing the image reconstruction quality. Patents CN103340641A and CN201210211462.9 disclose a dual ring structure, which includes a ring-shaped radiation source and a ring-shaped detector, wherein a gap is provided between the ring-shaped detectors, and the gap is for allowing the radiation to pass through to reach the detecting unit on the other side of the ring-shaped detector, and the existence of the gap may cause data loss and reduce image quality, and the structure also has another disadvantage that the central slice data cannot be obtained by axial scanning. The static CT scanner disclosed in patent CN201110247455 is also a double-ring structure, but the radiation source and the detector are placed in a staggered manner in the moving direction of the detected object, in this scanning structure, the radiation is not directed at the detector, the radiation passes through the object obliquely, the acquired data is seriously lost, the data integrity condition is seriously not met, the image is reconstructed by adopting an analytic reconstruction method, and the reconstruction accuracy is low. The image quality can be improved to a certain extent by a three-dimensional iterative reconstruction algorithm, but the calculation efficiency of the three-dimensional iterative reconstruction algorithm still cannot meet the actual application requirements, even if iterative reconstruction is adopted, the reconstructed image quality cannot reach the level of the radiation source and the detector which are right opposite, and the image quality requirement of medical CT imaging is very high, so that the structure has obvious defects for the medical CT imaging.

In the field of security inspection CT, both the american rapidscan company and the Surescan company have their own static CT products and corresponding patents such as US8451974B2 and US20060227932a1, and the american rapidscan company products (such as patent US8451974B2) adopt a double-ring structure, the whole structure includes a plurality of radiation sources arranged in a ring shape and a detector arranged in a ring shape, similar to patent CN201110247455, and the radiation sources and the detector are arranged in a staggered manner in the moving direction of the detected object, and the defect of data imperfection caused by the same oblique incidence exists. Products of Surescan (such as patent US20060227932A1) adopt a three-level scanning mode, each level is provided with a plurality of ray sources and a linear array detector, the ray sources are rapidly switched to simulate rotary motion, and the scanning mode is a multi-level static scanning mode; the method has the advantages that the ray source can be over against the detector, and the linear array detector can also effectively inhibit scattering through post collimation, but the scheme has lower image quality after iterative reconstruction because the ray source layout quantity is less; meanwhile, the length of the equipment is larger due to the adoption of a three-level scanning mode; in addition, since a plurality of ray sources share one linear array detector at each stage, the projection data of the scanned object is lost, and the quality of the reconstructed image is also reduced.

Disclosure of Invention

The invention aims to solve the problems, improve the time resolution of CT scanning and ensure the imaging quality of CT, and provides a non-rotary computed tomography device and a non-rotary computed tomography method.

The technical scheme adopted by the invention is as follows: a non-rotating computed tomography imaging apparatus, characterized by:

the device comprises an annular distributed ray source arranged on an outer ring, an annular detector arranged on an inner ring, a transmission device used for conveying a detected object, and a computer device used for controlling and processing data.

The distributed ray source consists of a plurality of sub ray sources, the focuses of the plurality of sub ray sources are positioned on the circumference of a circular ring, and the emitting port of each sub ray source is distributed with a collimator for limiting the beam range.

The annular detector is composed of a plurality of detector modules, and the centers of the plurality of detector modules are positioned on the circumference of another ring.

The circle of the focal point of the distributed ray source and the circle of the central points of the plurality of detector modules are concentric circles.

The distributed ray source can be switched rapidly.

The detector is divided into three sections, a center detector and two side detectors along the advancing direction of the detected object, the center detector is an area array detector, the area array detector is tightly arranged between the center detector and the center detector, and no air gap exists.

Preferably, the ray energy of the distributed ray source is between 40kV and 9 MeV.

Preferably, the distributed ray source is a cold cathode carbon nanotube ray source.

Preferably, the distributed radiation source is a hot cathode radiation source based on a grid control technology. The grid control technology is that a control grid is arranged between an anode target and a cathode, and the control grid can control the quick turn-on and turn-off of a ray source.

Preferably, the distributed radiation sources are equiangularly uniformly distributed.

Preferably, the distributed ray sources are non-equiangularly uniformly distributed.

Preferably, the central portion detector is a single-energy single-layer detector.

Preferably, the central portion detector is a photon counting detector.

Preferably, the two-sided partial detector is a single-energy single-layer detector.

Preferably, the two-sided partial detector is a photon counting detector.

Preferably, the two-side detector is a dual-energy double-layer detector; comprises two layers of detectors and a filter sheet positioned between the detectors at two sides.

According to some embodiments, the present invention provides a non-rotational computed tomography method characterized by:

in the imaging method, at least one sub-ray source works at the same time, and a plurality of sub-ray sources are rapidly switched to realize the sequential emission of rays of the whole circle of ray sources. In the imaging process, the sub-ray sources emit rays, the beam range is limited by the collimator, and the rays only pass through the central part of the annular detector close to one side of the sub-ray source emitting the rays, then pass through an object and are received by the detector module on the other side of the annular detector to realize signal acquisition.

The imaging method further comprises a projection data processing method, which comprises the following steps: and for the projection data of each visual angle, the signals received by the central detector and the signals received by the detectors at the two sides are included, the signals of the central detector and the signals of the detectors at the two sides are subjected to beam hardening correction uniformly, and the two final correction methods are unified under the same ray energy. Corrected projection data are obtained.

Preferably, the imaging method comprises the steps of:

s1: when the object to be measured moves at a constant speed along with the conveying device and enters the imaging range or stands still in the imaging range, the distributed ray sources rapidly switch the sub-ray sources according to a certain sequence, and the corresponding detector modules finish projection data acquisition.

S2: and dividing the acquired projection data into a central part projection and two side part projections, and executing a unified beam hardening correction process.

S3: and performing CT reconstruction according to the corrected projection data to obtain a hardening corrected tomographic image.

According to some embodiments, the present invention provides another non-rotational computed tomography method characterized by:

in the imaging method, at least one sub-ray source works at the same time, and a plurality of sub-ray sources are rapidly switched, so that the sequential ray emission of the whole circle of sub-ray sources is realized. In the imaging process, the sub-ray sources emit rays, the beam range is limited by the collimator, and the rays only penetrate through the central part of the annular detector, close to one side of the ray source emitting the rays, then penetrate through an object and are received by the detector module on the other side of the annular detector to realize signal acquisition.

The imaging method further comprises a projection data processing method, which comprises the following steps: and (3) respectively carrying out beam hardening correction on the signals of the central detector and the signals of the detectors at the two sides for the projection data of each visual angle, wherein the signals received by the detectors at the central part and the signals received by the detectors at the two sides are included, and finally, the two correction methods are unified under the same ray energy. A final projection data beam hardening correction is achieved.

Preferably, the imaging method comprises the steps of:

S2: the acquired projection data are divided into a central portion projection and two side portion projections, and respective beam hardening correction processes are performed.

S3: and merging the two parts of projection data corrected to the same energy, and performing CT reconstruction to obtain a hardened and corrected tomographic image.

Preferably, the CT reconstruction is an analytical reconstruction algorithm.

Preferably, the CT reconstruction is an iterative reconstruction algorithm.

Preferably, the distributed ray sources are rapidly switched according to a certain sequence, and the sequence can be emitted according to the position sequence of the distribution angles of the sub-ray sources.

Preferably, the distributed radiation sources are switched rapidly according to a certain sequence, which is a fixed sequence set in advance.

Preferably, the distributed radiation sources are rapidly switched in an order, which is a random order.

Preferably, the beam hardening correction method is a water correction method.

Preferably, the beam hardening correction method is a bone correction method.

Preferably, the beam hardening correction method is a water and bone combined correction method.

Preferably, the beam hardening correction method is a dual energy correction method.

Compared with the prior art, the beneficial effects are: firstly, the ray source and the detector do not rotate, and the rotation of the ray source and the detection can be simulated through the rapid switching of the ray source, so that the rotating speed of the ray source and the detector can be equivalently improved by accelerating the switching speed, the inspection speed is greatly improved, and the CT scanning time resolution is greatly improved; and secondly, as the ray source and the detector are opposite, and no gap exists in the middle of the detector, compared with the situation that a gap exists in the middle of oblique scanning and the detector, the data loss is effectively reduced, the projection data better conforms to the data completeness condition of image reconstruction, and the image reconstruction quality is greatly improved.

Drawings

Fig. 1 discloses a schematic two-dimensional cross-sectional structure of a double-ring structure, wherein the ray source and the detector are arranged oppositely, but a gap for the ray to pass through is arranged between the detectors.

FIG. 2 is a schematic diagram showing the relative positions of the radiation source and the detector in the full-circle layout of the radiation.

FIG. 3 is a schematic diagram showing the relative positions of the radiation source and the detector in the non-full-circle layout of the radiation.

FIG. 4 is a schematic diagram of a two-dimensional imaging cross-section structure with a double-ring structure, wherein the radiation source and the detector are arranged in a right-to-right manner, and no gap exists between the detectors.

Fig. 5 is a schematic diagram of a first detector structure.

Figure 6 is a schematic cross-sectional view of a second two-dimensional imaging configuration.

Fig. 7 is a schematic diagram of a second detector structure.

Fig. 8 is a schematic flow chart of an imaging method using a first detector configuration.

FIG. 9 is a flow chart illustrating an imaging method using a second detector configuration.

FIG. 10 is a schematic diagram of an imaging structure with a full-perimeter square layout of radiation sources.

FIG. 11 is a schematic diagram of an imaging structure with a non-full-circle square layout of the radiation sources.

FIG. 12 is a schematic diagram of an imaging structure of a full-circle polygon layout of a radiation source.

FIG. 13 is a schematic diagram of an imaging structure of a non-full-circle polygonal layout of a radiation source.

Fig. 14 is a schematic diagram of an imaging structure with a quadrilateral detector.

Fig. 15 is a schematic diagram of an imaging structure in which the detector is hexagonal.

The reference numbers in the figures illustrate: the detector comprises a 10 distributed ray source, a 10-1 sub ray source, an 11 collimator, a 13 annular detector, a 13-1 detector module, a 13-2 central detector, a 13-3 two-side detector, a 12 detector electronics part, a 14 gap between the detectors, a 15 ray bundle, 40 detector electronics rear radiation protection structural parts, 41 detector electronics front radiation protection structural parts, 42 detector PCB boards, 43 detector scintillators, 60 filter pieces, 61 two-side low-energy scintillators, 62 high-energy scintillators, 63 middle low-energy scintillators, and 64 boundaries of the central detector and the two-side detectors.

Detailed Description

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

A non-rotating computed tomography imaging apparatus comprising: the device comprises a ray source, a detector, a collimator, a transmission device for conveying a detected object, and a computer device for controlling and processing data. The method is characterized in that: the ray source is arranged on an annular distributed ray source 10 on the outer ring, and the detector is an annular detector 13 arranged on the inner ring.

The distributed radiation source 10 is composed of a plurality of sub-radiation sources 10-1, the focal points of the plurality of sub-radiation sources 10-1 are located on the circumference of a circular ring, and the emitting port of each sub-radiation source 10-1 is distributed with a collimator 11 for limiting the range of the beam 15.

The annular detector 13 is composed of a plurality of detector modules 13-1, and the centers of the plurality of detector modules 13-1 are located on the circumference of another ring.

The circle of the focal point of the distributed ray source 10 and the circle of the central points of the plurality of detector modules 13-1 are concentric circles.

The distributed radiation source 10 can be switched quickly.

Preferably, the radiation energy of the distributed radiation source 10 is between 40kV and 9 MeV.

Preferably, the distributed radiation source 10 is a cold cathode carbon nanotube radiation source.

Preferably, the distributed radiation source 10 is a hot cathode radiation source based on a grid control technique, in which a control grid is arranged between an anode target and a cathode, and the control grid can control the radiation source to be rapidly turned on and off.

Preferably, the distributed rays, 10, are equiangularly uniformly distributed.

Preferably, the distributed radiation sources 10 are non-equiangularly uniformly distributed.

Preferably, the central detector 13-2 is a single-energy single-layer detector.

Preferably, the central detector 13-2 is a photon counting detector.

Preferably, the two-sided detector 13-3 is a single-energy single-layer detector.

Preferably, the two-sided detector 13-3 is a photon counting detector.

Preferably, the two-side detector 13-3 is a dual-energy double-layer structure; including two layers of detectors and a filter 60 positioned between the two layers of detectors.

As shown in fig. 2, the layout of the distributed radiation source 10 and the annular detector 13 according to the present invention is a double-ring layout, the outer ring is the distributed radiation source 10, the inner ring is the annular detector 13, and the radiation source and the detector are arranged in a complete circle.

As shown in fig. 3, another layout manner for implementing the distributed ray source 10 and the annular detector 13 of the present invention is a double-ring layout, the outer ring is the distributed ray source 10, the inner ring is the annular detector 13, the distributed ray source 10 is a non-full-circle layout, the annular detector is a full-circle layout, and the ray source layout angle satisfies the CT half-scan condition.

As shown in fig. 4, to implement an embodiment of the present invention. In the imaging process, the distributed ray source 10 obtains a cone-shaped ray beam 15 with a certain angle through the collimator 11, the cone-shaped ray beam 15 passes through the radiation protection structural part 40 behind the detector electronics, and the radiation protection structural part 40 behind the detector electronics has the functions of protecting the detector electronics part 12 and absorbing scattered rays, so that scattering interference is reduced, and other parts are protected to a certain extent. The ray bundle 15 sequentially irradiates the detector PCB 42 and the detector scintillator 43, passes through the detector PCB 42 and the detector scintillator 43, and then acts with the opposite detector module 13-1 to generate projection data required by CT reconstruction. The ray bundle 15 and the detector scintillator 43 act to generate visible light signals, but a layer of reflective glue is coated outside the detector scintillator 43, so that visible light can be prevented from being emitted from the detector scintillator 43, and errors of ray signals caused by irradiation on other scintillators are avoided.

The distributed ray sources 10 are distributed on the outer ring and sequentially emit rays for a certain number of times, only 1 sub-ray source 10-1 emits a ray bundle 15 at a time point, or 2-3 sub-ray sources 10-1 simultaneously emit ray bundles 15, but it is required to ensure that the distribution areas of the receiving detector modules 13-1 corresponding to the emitted ray bundles 15 do not intersect, that is, the ray bundles 15 emitted simultaneously cannot irradiate the same detector module 13-1.

Fig. 5 is a structure of a detector and a protection component thereof according to the above embodiment, a detector electronics part 12 is disposed between a detector electronics rear radiation protection structure 40 and a detector electronics front radiation protection structure 41, the detector electronics rear radiation protection structure 40 is installed at one side of a corresponding sub-ray source 10-1, a detector scintillator 43 is installed between the two detector electronics parts 12, a detector PCB 42 is disposed between the detector electronics rear radiation protection structure 40 and the detector scintillator 43, and a gap through which a ray bundle 15 emitted from the sub-ray source 10-1 passes is disposed in the middle of the detector electronics rear radiation protection structure 40.

Fig. 6 and 7 show another embodiment of the present invention. In the imaging process, the distributed ray source 10 obtains a cone-shaped ray beam 15 with a certain angle through the collimator 11, the cone-shaped ray beam 15 passes through a gap between the radiation protection structural members 40 after detector electronics, and the radiation protection structural members 40 after the detector electronics have the functions of protecting the detector electronics part 12 and absorbing scattered rays, so that scattering interference is reduced, and other components are protected to a certain extent. The ray bundle 15 sequentially irradiates the detector PCB 42 and the detector scintillator 43, passes through the detector PCB 42 and the detector scintillator 43, and then acts with the opposite detector module 13-1 to generate projection data required by CT reconstruction.

When acting with the corresponding detector module 13-1, the radiation beam acts on the three segment detector, the three-section detector comprises a middle detector 13-2, two side detectors 13-3, a middle low-energy scintillator 63 and two side low-energy scintillators 61, the boundary between the two side low-energy scintillators 61 and the middle low-energy scintillator 63 is the boundary 64 between the middle detector 13-2 and the two side detectors 13-3, wherein for the intermediate detector 13-2 portion, the radiation beam 15 passes through only the intermediate low energy scintillator 61, resulting in a low energy projection signal, for the two side detectors 13-3, the beam 15 passes through the filter 60 and the detector PCB 42 to reach the high-energy scintillator 62, generating visible light, the visible light then interacts with a photodiode coupled to the crystal and produces a high-energy detection signal under the influence of the detector electronics 12. Thus, the middle detector obtains a single energy projection signal, while the two side detectors obtain dual energy projection signals.

Fig. 7 is a structure of a detector and a protection component thereof according to the above embodiment, a detector electronics part 12 is disposed between a detector electronics rear radiation protection structure 40 and a detector electronics front radiation protection structure 41, the detector electronics rear radiation protection structure 40 is installed at one side of a corresponding sub-ray source 10-1, a detector scintillator 43 is installed between the two detector electronics parts 12, a detector PCB 42 is disposed between the detector electronics rear radiation protection structure 40 and the detector scintillator 43, and a gap through which a ray bundle 15 emitted from the sub-ray source 10-1 passes is disposed in the middle of the detector electronics rear radiation protection structure 40. The annular detector 13 is divided into three sections, including a middle detector 13-2 and two side detectors 13-3 separated by the middle detector 13-2, and a boundary 64 is provided between the middle detector 13-2 and the two side detectors 13-3.

For the embodiment shown in fig. 4, a beam hardening correction method is included, which mainly includes the following steps:

s81: when the object to be measured moves at a constant speed along with the conveying device and enters the imaging range or stands still in the imaging range, the distributed ray sources 10 are rapidly switched according to a certain sequence, and the corresponding detector modules 13-1 complete projection data acquisition.

S82: and dividing the acquired projection data into a central part projection and two side part projections, and executing a unified beam hardening correction process.

S83: and performing CT reconstruction according to the corrected projection data to obtain a hardening corrected tomographic image.

For the embodiments shown in fig. 6 and 7, a beam hardening correction method as shown in fig. 9 is included, which mainly includes the following steps:

s91: when the object moves at a constant speed along with the conveying device and enters an imaging range or stands still in the imaging range, the distributed ray sources 10 are rapidly switched according to a certain sequence, and the corresponding detector modules 13-1 finish projection data acquisition.

S92: the acquired projection data are divided into a center portion projection and two side portion projections, and a beam hardening correction process is performed on the middle portion detector data.

S93: the acquired projection data is divided into a center portion projection and two side portion projections, and a beam hardening correction process is performed on the two side portion detector data.

S94: and merging the two parts of projection data of the middle part and the two sides after the two parts are corrected to the same energy, and carrying out CT reconstruction to obtain a hardened and corrected tomographic image.

Fig. 10, fig. 11, fig. 12, and fig. 13 show other layouts of the distributed radiation source 10 and the annular detector 13, which at least include one of a circle, an ellipse, a triangle, a square, a rectangular square, a hexagon, an octagon, and other polygons, or partial patterns thereof, and spatial layouts of the polygons may all implement the solution of the present invention.

Fig. 14 and 15 are distribution patterns of distributed ray sources and multi-segment linear detectors, the layout pattern of the detectors at least includes one of a circle, an ellipse, a triangle, a square, a rectangular square, a hexagon, an octagon and other polygons or partial patterns thereof, and the polygonal spatial layout of the detectors can all implement the technical solution of the present invention.

The above examples are intended only to illustrate the claimed invention, but not to limit the claimed scope of the invention. The position of each component in the above examples can be changed by those skilled in the art, and all the changes are within the scope of the present invention; modifications and substitutions by one of ordinary skill in the art within the scope of the present invention are considered to be within the scope of the present invention.

Claims

1. A non-rotating computed tomography imaging apparatus, characterized by:

the device comprises an annular distributed ray source arranged on an outer ring, an annular detector arranged on an inner ring, a transmission device used for conveying a detected object and a computer device used for controlling and processing data; the distributed ray source is composed of a plurality of ray source modules, and a plurality of ray source focuses are positioned on the circumference of a circular ring; the annular detector consists of a plurality of detector modules, and the centers of the detector modules are positioned on the circumference of the other ring; the circle of the focal point of the distributed ray source is concentric with the circle of the central points of the plurality of detector modules; the distributed ray source can be switched rapidly; the detector is divided into three sections along the advancing direction of the detected object, a central detector and two side detectors, wherein the central detector is an area array detector, pixels are closely arranged, and no air gap exists.

2. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the distributed ray source is a cold cathode carbon nano tube ray source or a hot cathode ray source based on a grid control technology.

3. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the distributed ray sources are distributed uniformly in equal angles.

4. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the distributed ray sources are distributed in an unequal angle and uniform distribution.

5. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the central part detector is a single-energy single-layer detector or a photon counting detector.

6. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the detectors at the two side parts are single-energy single-layer detectors or photon counting detectors.

7. The non-rotating computed tomography imaging apparatus of claim 1, wherein: the two side part detectors are dual-energy double-layer detectors; comprises two layers of detectors and a filter sheet positioned between the detectors at two sides.

8. A non-rotational computed tomography method, characterized by:

in the imaging method, at least one ray source works at the same time, and the ray sources are rapidly switched, so that the sequential ray emission of the whole circle of ray sources is realized. During imaging, the ray source emits rays, and the beam range is limited, so that the rays only pass through the central part of the annular detector close to one side of the ray source emitting the rays, then pass through an object and are received by the detector on the other side of the annular detector to realize signal acquisition. Uniformly carrying out beam hardening correction on the acquired detector signals to obtain corrected projection data;

the imaging method comprises the following steps:

s1: when the articles enter an imaging range or stand in the imaging range along with the uniform motion of the conveying device, the distributed ray sources are rapidly switched according to a certain sequence, and the corresponding detectors complete the acquisition of projection data;

s2: dividing the collected projection data into a central part projection and two side part projections, and executing a unified beam hardening correction process;

s3: and performing CT reconstruction according to the corrected projection data, wherein the CT reconstruction is an analytic reconstruction algorithm or an iterative reconstruction algorithm, and a hardened and corrected tomographic image is obtained.

9. A non-rotational computed tomography method, characterized by:

in the imaging method, at least one ray source works at the same time, and the ray sources are rapidly switched, so that the sequential ray emission of the whole circle of ray sources is realized. In the imaging process, the ray source emits rays, and the beam range is limited, so that the rays only penetrate through the central part of the annular detector, which is close to one side of the ray source emitting the rays, then penetrate through an object, and are received by the detector on the other side of the annular detector to realize signal acquisition;

the imaging method further comprises a processing method of the projection data, and the processing method comprises the following steps: and (3) respectively carrying out beam hardening correction on the signals of the central detector and the signals of the detectors at the two sides for the projection data of each visual angle, wherein the signals received by the detectors at the central part and the signals received by the detectors at the two sides are included, and finally, the two correction methods are unified under the same ray energy. Implementing a final projection data beam hardening correction;

the imaging method comprises the following steps:

s2: dividing the acquired projection data into a central part projection and two side part projections, executing respective beam hardening correction processes, and correcting to uniform energy;

s3: and converging the corrected two parts of projection data, and performing CT reconstruction, wherein the CT reconstruction is an analytic reconstruction algorithm or an iterative reconstruction algorithm, so as to obtain a hardened and corrected tomographic image.

10. A non-rotational computed tomography method according to claim 11 or 12, characterized in that:

the distributed ray sources are rapidly switched according to a certain sequence, and the sequence can be emitted according to the position sequence of the ray source distribution angles;

the distributed ray sources are rapidly switched according to a certain sequence, and the sequence is a preset fixed sequence.