CN118402805B

CN118402805B - Large-field CT imaging method, device, system, electronic equipment and storage medium

Info

Publication number: CN118402805B
Application number: CN202410847462.0A
Authority: CN
Inventors: 蒋小宝; 姚玉成; 马骏骑; 汪令行; 彭玟滔
Original assignee: Hefei Yofo Medical Technology Co ltd
Current assignee: Hefei Yofo Medical Technology Co ltd
Priority date: 2024-06-26
Filing date: 2024-06-26
Publication date: 2024-09-20
Anticipated expiration: 2044-06-26
Also published as: CN118402805A

Abstract

The application provides a large-field CT imaging method, which relates to the technical field of CBCT imaging and comprises the following steps: determining a starting position of the detector according to a required imaging region of interest by the system; the rotating seat starts to accelerate to a position with an angle of 0 DEG, and the detector moves in the horizontal direction; when the rotary seat finishes a fixed angle rotation, starting a detector vertical direction moving motor to control the detector to move to a new height; the patient is imaged for the second time by the source and the detector, and the detector moves horizontally at the new height position, so that the reconstruction of the large visual field in the vertical direction is completed after the rotation of the rotary seat is continuously completed by a fixed angle. According to the application, the imaging position can be arbitrarily controlled within a large imaging range by moving the detector, and a patient can finish non-spliced large-field reconstruction by rotating the detector within 450 degrees on the seat, so that the required imaging time is shorter, the rotation angle is smaller, and the movement of the rotating motor is simpler.

Description

Large-field CT imaging method, device, system, electronic equipment and storage medium

Technical Field

The invention relates to the technical field of CBCT imaging, in particular to a large-field CT imaging method, a device, a system, electronic equipment and a storage medium.

Background

Most of the conventional CBCT reconstruction techniques today have a detector fixed relative to a radiation source, which is rotated about an imaging field of view. Because the detector and source are relatively fixed, the imaging region of the overall system is limited to the FOV of the detector, and therefore the size of the imaging region is limited by the detector size. In order to increase the imaging area of CBCT, the most common method is to increase the size of the detector, but this method will greatly increase the cost of the whole apparatus; another method for enlarging the imaging area in the vertical direction is two-circle scanning, and the specific method is that firstly, the detector and the source scan and image the target at a first height, then the detector and the source integrally translate upwards for a certain distance to reach a second height, then the target is imaged again at the second height, and then the imaging results at the two heights are spliced to obtain a large-view reconstruction result in the vertical direction. Although the method of moving the detector and the source as a whole can effectively increase the imaging field of view and does not cause significant increase in cost, the method is the most widely used method in the market at present, but the method is still limited by the fact that the mechanical structures of the detector and the source are relatively fixed, and although a larger imaging field of view can be realized in the vertical direction, the imaging area in the horizontal direction is still limited by the size of the detector; and it requires two scans, greatly increasing the scan time.

Disclosure of Invention

The invention aims at: the CBCT imaging device aims at solving the problems that in the prior art, a CBCT moving a detector is relatively fixed with a source in an imaging process, so that an imaging area is limited, and the imaging field of view in the vertical direction can only be improved, and the imaging field of view in the horizontal direction can not be improved due to the integral movement of the detector and the source.

In order to achieve the above object, the present invention provides the following technical solutions:

A large field CT imaging method comprising the steps of:

S10: before shooting is started, determining the starting position of a detector according to a required imaging region of interest through a system;

S20: when the detector moves to the initial position, the rotary seat starts to accelerate to a position with an angle of 0 DEG, then starts to rotate at a constant speed, and simultaneously the detector moves in the horizontal direction to perform first imaging;

s30: when the rotary seat completes the rotation of a fixed angle, the first shooting is completed, the fixed angle completed by the rotary seat is specifically 180 degrees plus 2Y, the detector vertical direction moving motor is started, the detector is controlled to move to a new height, the new height to which the detector is moved is specifically set to be h, and the rotation angle of the seat is ；

S40: when the detector moves to a new height, the source and the detector perform secondary imaging on the patient, the rotary seat still moves at a uniform speed, and the detector moves horizontally at the position of the new height;

S50: and after the rotary seat continues to finish rotation at a fixed angle, all shooting processes are finished, and the reconstruction of the large visual field in the vertical direction is finished.

In the preferred technical scheme of the application, in the S10, in the direction of 0 ° vertically upwards, when the angle between the reconstruction center and the rotation center is θ, the initial position of the detector can be determined by calculating the imaged ROI position through a formula.

In S20, the rotating angle of the swivel seat is set to beThe range of the motion detector is [0,180 degrees+2Y ], Y is the corresponding fan-shaped angle under the maximum stroke, and the motion position of the detector can be calculated through a formula.

In the preferred embodiment of the present application, in S40, the angle through which the rotating seat rotates after the detector moves to the new height h is set asAnd (2) andThe range of the values is as followsThe motion track of the detector in the horizontal direction at the position with the vertical new height h can be calculated through a formula.

In the preferred embodiment of the present application, in S50, a fixed angle at which the swivel seat is continuously completed is specifically 180 ° +2y.

As a preferable technical scheme of the application, the application further comprises a weighting method capable of carrying out weighted reconstruction on data of different heights and different phases, wherein a specific weighting formula is as follows:

；

Wherein, Is at the sourceUnder the angle, the opposite sector opening angle isFinal weighted result values of the projections of the point to be reconstructed,And (3) withThe result values of the two projection values of the point to be reconstructed of the detector under the first height weighted by the park weight are respectively the projection values under 0 degrees and 180 degrees,And (3) withThe result values of the two projection values of the point to be reconstructed of the detector under the second height weighted by the park weight are respectively the projection values under 0 degrees and 180 degrees,And (3) withThe weights of the detector gray values at the first height and the detector gray values at the second height are respectively.

As a preferred technical solution of the present application, the weighting method includes the following steps:

s1: first, a projection image at a first height is captured Performing park weight weighting and some preprocessing of reconstruction;

s2: capturing projection images at a second height, for each angle Weighting the Parker weight, and preprocessing the Parker weight;

s3: weighting the processed data with a first height and a second height, and for the obtained second height The projection data at the angle, as well as the same angle data and 180 deg. complementary data at the first height present, are weighted.

As a preferred technical solution of the present application, the step S3 includes the following steps:

s31: calculating projection data at the same angle at a first height If the gray value exists, the gray value is taken, and if the gray value does not exist, the gray value is set to be 0;

S32: calculate a first height Projection data under 180 degrees corresponding to angleIf the gray value exists, the gray value is taken, and if the gray value does not exist, the gray value is set to be 0;

s33: calculating weights Calculating the reconstruction points of the band according to the geometric parametersRespectively calculating weights from the distances between the positions of the projection points of the detectors, which fall on the detectors, and the upper and lower surfaces of the detectors when the detectors are located at different heights;

S34: calculating the second height projection data obtained in step S2 Projection data weights at a corresponding first heightCorrecting the weight according to whether the data corresponding to 180 degrees exist or not;

S35: the final weighting method comprises the following steps: 。

S4: for the scanning data of different angles under the second height, the weighting of one angle can be completed when the data under one scanning angle is obtained, and when all the data are And (3) completing all scanning of the data under the angles, namely completing weighting of all angles, and obtaining a final vertical large-field imaging result.

The invention provides a large-field CT imaging device, comprising: an X-ray source: an X-ray emitting assembly; the detector comprises: located opposite the X-ray source for capturing X-rays passing through the scanned object; a rotating mechanism: including mechanical structures for supporting and rotating the X-ray source and detector; positioning structure: comprises a patient seat, a jaw support and a dental support column, which are used for fixing and adjusting the position of a patient in the scanning process; safety device: including radiation shielding and emergency stop button structures, ensure operator and patient safety.

The invention provides an electronic device, comprising: a memory storing execution instructions; and a processor executing the execution instructions stored in the memory, so that the processor executes the large-field CT imaging method according to any one of the above embodiments.

The present invention provides a readable storage medium having stored therein execution instructions which when executed by a processor are configured to implement a large field CT imaging method as described in any of the above embodiments.

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

The detector is moved to a preset position, the height is a first height position, the detector can capture an initial image of a patient, the control system controls the seat to rotate and drives the patient to rotate around the constant angular speed of the rotation center from the position, the detector synchronously moves along a preset horizontal track to complete continuous imaging, after the patient rotates for 210 degrees, the vertical direction moving motor is started, the detector is controlled to move to a second height position, the patient still keeps constant speed to rotate, after the patient continues to rotate for 20 degrees, the detector moves to the second height position, then the radiation source starts to start paying off for the second time, after the patient rotates for 210 degrees, the paying off is stopped, the detector can capture a large-view image in the vertical direction at the second height position, so that the imaging position can be arbitrarily controlled in a large imaging range by moving the detector, and the patient can complete non-spliced large-view reconstruction only by rotating for 450 degrees on the seat.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a perspective view of the system of the present invention;

FIG. 3 is a top view block diagram of the system of the present invention;

FIG. 4 is a schematic view of the initial position of the detector according to the present invention;

FIG. 5 is a schematic diagram of data weighting according to the present invention;

FIG. 6 is a schematic diagram of a large field CT imaging device in accordance with one embodiment of the present invention;

FIG. 7 is a schematic diagram of a large field-of-view CT imaging system employing a hardware implementation of a processing system in accordance with another embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It will be apparent that the described embodiments are some, but not all, embodiments of the invention.

Example 1:

as shown in fig. 1, 2 and 3, the present embodiment proposes a large-field CT imaging method, including the steps of:

Specifically, before shooting is started, the system determines the initial position of the detector according to the required imaging region of interest, and when the angle between the reconstruction center and the rotation center is θ, the specific calculation formula of the initial position of the detector is as follows:

；

Before a patient is imaged by the detector, a control system in the CBCT apparatus determines a starting position of the detector according to a required imaging region of interest, as shown in fig. 1 and 2, a distance between a reconstruction center and a rotation center is r, and in a direction of 0 ° in a vertical direction, when an angle between the reconstruction center and the rotation center is θ, the starting position of the detector can be obtained by calculation according to the above formula, wherein r is a distance between the reconstruction center and the rotation center, SID is a distance from a source to a plane of the detector, SAD is a distance from the source to the rotation center, For maximum detector travel, the system can determine the initial detector position based on the desired imaging ROI position (r, θ) according to the above equation.

specifically, when the detector moves to the initial position, the rotary seat starts to accelerate to a position with an angle of 0 degrees, then starts to rotate at a uniform speed, and meanwhile, the detector moves in the horizontal direction, the movement position can be controlled by the rotating angle of the rotary seat, and the specific calculation formula of the movement position is as follows:

；

Wherein after the detector moves to the initial position, the rotary seat starts to accelerate to a position with an angle of 0 DEG, the rotary seat needs to accelerate and rotate at a constant speed, then rotate at a constant speed, and finally rotate at a reduced speed, at the same time, the detector moves in the horizontal direction, and the movement position of the detector can be calculated by the formula, For the rotation of the seat through an angle ranging from [0,180 ° +2y ], Y being the corresponding fan angle at maximum travel, the remaining parameters are identical to those of step S110, at which stage the source and detector begin to image the patient for the first time.

S30: when the rotating seat completes the rotation of a fixed angle, completing the first shooting, starting a detector vertical direction moving motor, and controlling the detector to move to a new height;

Specifically, when the rotating seat completes the rotation of 180 degrees+2Y angles, the first shooting is completed, the vertical direction moving motor of the detector is started, the detector is controlled to move upwards, after the rotating seat moves by a fixed angle, the detector moves upwards to a height h, and the rotating angle of the seat is 。

Specifically, when the detector moves to a second height position with the height h, the source and the detector perform second imaging on the patient, at this time, the rotating seat still moves at a uniform speed, the detector moves horizontally at the position with the vertical height h, the movement track is still controlled by the angle rotated by the seat, and the specific calculation formula of the movement track is as follows:

；

Wherein when the detector moves from the first height position of the initial position to the second height position with the height h, the source and the detector simultaneously start to image the patient for the second time, and the running track of the detector can be calculated according to the rotating angle of the seat through the formula at the moment, wherein, To rotate the seat through the angle after the detector has moved to height h,The range of the values is as followsWhen (when)When the height is 0, S is the initial position of the detector in the horizontal direction when the height is h.

It should be noted that the specific operation steps of the imaging method of the present application are as follows:

1: configuring the detector to a preset first height;

Specifically, the detector is positioned at a predetermined height that is set based on the patient's body shape and the desired imaging region, i.e., a first height position that enables the detector to effectively capture an initial image of the patient, providing a reference point and fiducial for subsequent imaging procedures.

In addition, the detector can move in the horizontal direction and the vertical direction in the detection plane, the detector moving plane can be regarded as a huge virtual detector, the virtual detector and the source can form an imaging system, and the imaging field of view of the virtual detector is like the rectangular area in fig. 1, so that the imaging area of the CBCT imaging system can be any position in the large rectangular area, and the positioning reconstruction of the large field of view in the vertical direction can be realized.

2: Controlling the patient to rotate around the constant angular speed of the rotation center, enabling the detector to synchronously move along a preset horizontal track, and starting the ray source to carry out first paying-off and continuous imaging by matching with the detector;

In particular, in this step, the patient is first fixed on a rotatable table, the constant angular velocity of rotation is set by the control system, and at the same time the detector is moved along a horizontal trajectory according to a preset program, this synchronous movement allowing the detector to perform continuous imaging while maintaining a stable relative position to the patient.

3: After the patient finishes 210 DEG rotation, activating a vertical direction moving motor to work and adjust the detector to move from a first height position to a second height position;

Specifically, after a specified 210 rotation is completed, the control system activates a motor for vertical movement of the detector, which motor can move the detector up or down from a first elevation position to a second elevation position, the position being varied to capture images from different perspectives to provide more comprehensive diagnostic information.

4: After the detector reaches the second elevation position, maintaining a constant rotational speed of the patient until an additional 20 ° of rotation;

In particular, the control system can ensure that the patient continues to maintain the original constant rotational speed during the detector adjustment, when the detector reaches a new height position, i.e. the second height position, and the patient continues to complete an additional 20 ° rotation, which is ready for the subsequent imaging step.

5: Starting the ray source to pay off for the second time, wherein the starting time of paying off is synchronous with the time when the patient reaches 230 DEG total rotation angle;

in particular, when the patient rotates together to 230 °, the radiation source is activated to start emitting, and the radiation source is synchronously started to ensure that the radiation source emitting is accurately aligned with the position of the patient, so as to optimize imaging quality.

6: Stopping paying off the ray source after the patient rotates 210 degrees again, and capturing a large-field image in the vertical direction at a second height position by the detector;

After the patient completes the subsequent 210 DEG rotation, the ray source is turned off and the radiation emission is stopped, at the moment, the detector can capture a vertical large-field image at the second height position, and the detector is usually used for evaluating the imaging of a large area in the patient, such as the whole spine or the whole trunk, so that the detector is fixed on a large detector plane guide rail, the imaging position can be arbitrarily controlled in a large imaging range by moving the detector, and the patient can complete the non-spliced large-field reconstruction only by rotating the detector within 450 DEG on a seat.

Example 2:

In order to achieve non-spliced large-field imaging within 450 degrees, the application also discloses a weighting method, so that data between different phases can be normally weighted and reconstructed, because the detector has partial overlapping with the reconstruction field of view when the height is 1 when the height is 0, and in order to effectively eliminate data redundancy, projection data of the same position of a region to be reconstructed of the detector needs to be weighted, and because the method can achieve large-field reconstruction only by scanning 450 degrees, imaging angles of the detector at different heights are not in one-to-one correspondence, the weighting method provided by the application can ensure that the data between different angles are weighted.

As shown in fig. 4 and 5, as a preferred embodiment, based on the foregoing manner, the large-field CT imaging method further includes: the weighting method capable of carrying out weighted reconstruction on the data of different heights and different phases comprises the following specific weighting formulas:

；

It should be noted that, in an imaging system, it is required to obtain a complete reconstruction result, for a point P to be reconstructed, a 180 ° ray needs to pass through the point, and for fig. 4, the anticlockwise direction is positive, S1 is a source with a source angle β, and when the point P to be reconstructed is a projection point with a field angle P when the source projects from S1; s3 is the position of the source S1 after rotating 180 degrees, S2 is the position of the source capable of reconstructing the point alpha to be reconstructed by 180 degrees compared with the position of the source S1 by 180 degrees, the geometrical relationship of the system shows that the angle of the source S3 is 180 degrees+beta, and the angle of the source S2 is 180 degrees+beta-2 alpha, therefore, for the point P (alpha, beta, sigma) to be reconstructed defined by angles, wherein alpha is the fan-shaped opening angle of the point to be reconstructed, beta is the angle of the source, sigma is the opening angle in the vertical direction, beta is the angle of the rotating seat, and for the system, beta is the angle of rotating the rotating seat, and because the rotation angles are 180 degrees+2gamma in the imaging of the detector under different heights, the condition of sufficiency of reconstructed data can be met, so that the point P2 (alpha, beta, sigma) to be reconstructed under the second height can be found under the first height corresponding to the angle of 0 degrees or 180 degrees, and the points P1 (alpha, beta, sigma) can be found under the first height, so that the redundant phenomenon can be eliminated by the above formula, the redundant data can be effectively reconstructed by the two different heights, and the redundant data can be prevented from being partially overlapped.

Wherein, Is at the sourceUnder the angle, the opposite sector opening angle isFinal weighted result values of the projections of the point to be reconstructed,And (3) withThe result values of the two projection values of the point to be reconstructed of the detector under the first height weighted by the park weight are respectively the projection values under 0 degrees and 180 degrees,And (3) withThe result values of the two projection values of the point to be reconstructed of the detector under the second height weighted by the park weight are respectively the projection values under 0 degrees and 180 degrees,And (3) withThe weights of the detector gray values at the first height and the detector gray values at the second height are respectively calculated according to the prior art, and are not described herein.

Furthermore, in the above-mentioned weighting formula, for the projection map obtained at the second height, only the data at the current angle need to be considered, and the data corresponding to the angle of 180 ° need not to be considered, because in the second height, the weighting method of the present application corrects the weights according to the angles, so that the final weighting result can be obtained by traversing the data of all the projection angles, so that the weighting method of the present application specifically further includes the following steps:

Specifically, the image taken of the patient with the detector at the initial first elevation position may be subjected to reconstruction preprocessing by park weight weighting.

S2: capturing projection images at a second height, for each angleWeighting the Parker weight, and preprocessing the Parker weight;

specifically, the detector, after being moved to the second height position by the motor, may perform a reconstruction preprocessing operation on the images taken by the patient, with park weight weighting for each image taken.

S3: weighting the processed data with a first height and a second height, and for the obtained second heightThe projection data at the angle, the same angle data and 180 ° complementary data at the first height present are weighted;

specifically, after the images captured by the detector at the first and second heights are preprocessed, the preprocessed data is weighted by the first and second heights, and finally the obtained second height is used for The projection data at the angle, as well as the same angle data and 180 deg. complementary data at the first height present, are weighted.

Further, the step S3 specifically further includes the following steps:

Specifically, projection data at the same angle at the first height is first calculated and recorded as If the data exists, the gray value is taken, and if the data does not exist, the gray value is set to 0.

Wherein,

；

S32: calculate a first heightProjection data under 180 degrees corresponding to angleIf the gray value exists, the gray value is taken, and if the gray value does not exist, the gray value is set to be 0;

Specifically, a first height is calculated Projection data corresponding to the angle of 180 degrees is recorded asIf the data exists, the gray value is taken, and if the data does not exist, the gray value is set to 0.

Wherein,

；

S33: calculating weightsCalculating the reconstruction points of the band according to the geometric parametersRespectively calculating weights from the distances between the positions of the projection points of the detectors, which fall on the detectors, and the upper and lower surfaces of the detectors when the detectors are located at different heights;

Specifically, the weights are calculated and noted as Then according to the geometric parameters, calculating the reconstruction pointsThe position of the projection point on the detector when the detector is at different heights and the distance from the detector to the upper and lower parts are weighted.

S34: calculating the second height projection data obtained in step S2Projection data weights at a corresponding first heightCorrecting the weight according to whether the data corresponding to 180 degrees exist or not;

Specifically, the projection data weight at the corresponding first height under the second height projection data obtained in step S2 is calculated and recorded as The second height projection data is recorded asAnd finally, correcting the weight according to whether the data corresponding to 180 degrees exist.

Wherein,

；

S35: the final weighting method comprises the following steps:。

for the above weighting method, the present application further includes the following steps:

S4: for the scanning data of different angles under the second height, the weighting of one angle can be completed when the data under one scanning angle is obtained, and when all the data are The data under the angles are completely scanned, namely, the weighting of all the angles is completed, and a final vertical large-field imaging result is obtained;

Specifically, after the data of different angles under the second height are scanned, weighting of one angle can be completed every time the data under one scanning angle is obtained, so that when the data under all angles are completely scanned, weighting of all angles is completed, and finally a final vertical large-field imaging result can be obtained.

Example 3

Fig. 6 is a schematic diagram of a large field-of-view CT imaging apparatus according to one embodiment of the present invention. Referring to fig. 6, the present invention further provides a large field CT imaging apparatus 1000. The large field CT imaging apparatus 1000 of the present embodiment may include an X-ray source 1002, a detector 1004, a rotation mechanism 1006, a positioning structure 1008, and a safety device 1010.

The X-ray source 1002 is a critical component whose primary function is to emit X-rays, which is a relatively high energy electromagnetic wave that can penetrate most substances. In the field of medical imaging, an X-ray source generates X-rays by high-speed collisions of an electron beam with a target material (typically tungsten or molybdenum). These X-rays are directed and precisely directed onto the scanned object to acquire an image of the internal structure. The design and power of the X-ray source determines the intensity and quality of the X-rays produced, thereby directly affecting the resolution and detail resolution of the imaging result.

The detector 1004 is located opposite the X-ray source and is responsible for capturing X-rays after passing through the scanned object. The detectors may be based on different technologies such as photodiode arrays, phosphor screens or other photosensitive materials. As X-rays pass through an object being scanned, such as a human body part, tissues of different densities and compositions absorb X-rays to different extents, and these differences are captured by a detector and converted into electrical signals, which are then converted into image data. These images can show the internal structure of the scanned object, which is particularly important for medical diagnostics.

The rotation mechanism 1006 includes a set of mechanical structures for supporting and rotating the X-ray source and detector. This allows the device to perform a 360 degree full scan around the scanned object. In this way, data may be acquired from multiple angles, which may then be used to reconstruct a three-dimensional image or a more detailed two-dimensional slice image. Accurate control of the rotation mechanism is critical to ensure image quality and reduce scanning errors.

The positioning structure 1008 is a device designed to fix and adjust the position of the patient during a scan. This typically includes patient seating, jaw braces and dental braces, which not only ensure patient comfort during scanning, but also maintain patient stability, thereby reducing image blurring due to movement. The design of the positioning structure aims at adapting to patients with different body types and requirements, and is easy for an operator to adjust, so that the scanning accuracy and efficiency are ensured.

The safety device 1010 is an important part of securing the safety of the operator and the patient. This includes radiation shielding, such as lead plates or other radiation shielding materials, for blocking and absorbing scattered X-rays, preventing exposure of personnel to the radiation. In addition, the emergency stop button configuration allows for quick power shut down in the event of an accident or equipment failure, immediate shut down of the equipment operation to prevent further potential harm to the patient and operator. The design and maintenance of safety devices is critical to ensuring the safety of the operation of medical equipment.

Example 4

Fig. 7 is a schematic diagram of a large field-of-view CT imaging system 1100 employing a hardware implementation of a processing system in accordance with another embodiment of the invention. Referring to fig. 7, the present invention further provides a large-field CT imaging system 1100, and the large-field CT imaging system 1100 of the present embodiment may include a target image generating module 1101, a display module 1102, a receiving module 1104, a region of interest determining module 1105, a reconstruction region determining module 1106, and an image reconstructing module 1108.

It should be noted that, details not disclosed in the large-field CT imaging system 1100 of the present embodiment may refer to details disclosed in the large-field CT imaging method M100 of the foregoing embodiment, which are not described herein.

The large field-of-view CT imaging system 1100 may include corresponding modules that perform each or several of the steps of the flowcharts described above. Thus, each step or several steps in the flowcharts described above may be performed by respective modules, and the apparatus may include one or more of these modules. A module may be one or more hardware modules specifically configured to perform the respective steps, or be implemented by a processor configured to perform the respective steps, or be stored within a computer-readable medium for implementation by a processor, or be implemented by some combination.

The hardware architecture of the large field-of-view CT imaging system 1100 may be implemented using a bus architecture. The bus architecture may include any number of interconnecting buses and bridges depending on the specific application of the hardware and the overall design constraints. Bus 1500 connects together various circuits including one or more processors 1200, memory 1300, and/or hardware modules. Bus 1500 may also connect various other circuits 1400, such as peripherals, voltage regulators, power management circuits, external antennas, and the like.

Bus 1500 can be an industry standard architecture (ISA, industry Standard Architecture) bus, a peripheral component interconnect (PCI, PERIPHERAL COMPONENT) bus, or an extended industry standard architecture (EISA, extended Industry Standard Component) bus, among others. The buses may be divided into address buses, data buses, control buses, etc. For ease of illustration, only one connection line is shown in the figure, but not only one bus or one type of bus.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention. The processor performs the various methods and processes described above. For example, method embodiments of the present invention may be implemented as a software program tangibly embodied on a machine-readable medium, such as a memory. In some embodiments, part or all of the software program may be loaded and/or installed via memory and/or a communication interface. One or more of the steps of the methods described above may be performed when a software program is loaded into memory and executed by a processor. Alternatively, in other embodiments, the processor may be configured to perform one of the methods described above in any other suitable manner (e.g., by means of firmware).

Logic and/or steps represented in the flowcharts or otherwise described herein may be embodied in any readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions.

It should be understood that portions of the present invention may be implemented in hardware, software, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or part of the steps implementing the method of the above embodiments may be implemented by a program to instruct related hardware, and the program may be stored in a readable storage medium, where the program when executed includes one or a combination of the steps of the method embodiments. The storage medium may be a volatile/nonvolatile storage medium.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, each unit may exist alone physically, or two or more units may be integrated into one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product. The storage medium may be a read-only memory, a magnetic disk or optical disk, etc.

The invention also provides an electronic device, comprising: a memory storing execution instructions; and a processor or other hardware module that executes the memory-stored execution instructions, causing the processor or other hardware module to perform the image processing method of any of the above embodiments.

The present invention also provides a computer-readable storage medium having stored therein execution instructions which, when executed by a processor, are to implement the image processing method of any of the above embodiments.

For the purposes of this description, a "readable storage medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable read-only memory (CDROM). In addition, the readable storage medium may even be paper or other suitable medium on which the program can be printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner if necessary, and then stored in a memory.

In the description of the present specification, the descriptions of the terms "one embodiment/mode," "some embodiments/modes," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily the same embodiments/modes or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/implementations or examples described in this specification and the features of the various embodiments/implementations or examples may be combined and combined by persons skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

It will be appreciated by persons skilled in the art that the above embodiments are provided for clarity of illustration only and are not intended to limit the scope of the invention. Other variations or modifications of the above-described invention will be apparent to those of skill in the art, and are still within the scope of the invention.

Claims

1. The large-field CT imaging method is characterized by comprising the following steps of:

S30: when the rotary seat completes the rotation of a fixed angle, the first shooting is completed, the fixed angle completed by the rotary seat is specifically 180 degrees+2Y, wherein Y is a corresponding first fan-shaped angle under the maximum stroke, a detector vertical direction moving motor is started, the detector is controlled to move to a new height, the new height to which the detector moves is specifically set h, and the seat rotating angle is ，Indicating the angle the seat has rotated during the movement of the detector to h;

s40: when the detector moves to a new height, the source and the detector perform secondary imaging on the patient, the rotary seat moves at a constant speed at the moment, the detector moves horizontally at the position of the new height, and the angle rotated by the rotary seat after the detector moves to the new height h is set as And (2) andThe range of the values is as followsGamma is the corresponding second fan angle under the maximum travel, and the motion track of the detector in the horizontal direction at the position with the vertical new height h can be calculated through a formula

S50: when the rotary seat continues to finish rotation at a fixed angle, all shooting processes are finished, and the reconstruction of the large visual field in the vertical direction is finished;

the large-field CT imaging method comprises a weighting method capable of carrying out weighted reconstruction on data of different heights and different phases, and a specific weighting formula is as follows:

；

Wherein, Is at the sourceUnder the angle, the opposite sector opening angle isThe final weighted result value of the projection of the point to be reconstructed, sigma represents the opening angle of the point to be reconstructed and the vertical direction of the source, namely the opening angle of the z direction, P ₁₁ (alpha, beta, sigma) and P ₁₂（-α、β₁ plus pi-2 alpha) are the result values of the two projection values of the point to be reconstructed, which are weighted by the Peak weight, of the detector under the first height, the result values are respectively the projection values under 0 DEG and 180 DEG, P ₂₁ (alpha, beta, sigma) and P ₂₂（-α、β₁ plus pi-2 alpha, sigma) are the result values of the two projection values of the point to be reconstructed, which are weighted by the Peak weight, of the detector under the second height, the result values are respectively the projection values under 0 DEG and 180 DEG,And (3) withRespectively weighing the gray value of the detector at the first height and the gray value of the detector at the second height;

the weighting method comprises the following steps:

s3: weighting the processed data with a first height and a second height, and for the obtained second height The projection data at the angle, the same angle data and 180 ° complementary data at the first height present are weighted; the step S3 comprises the following steps:

S35: the final weighting method comprises the following steps: 。

2. The method according to claim 1, wherein in S10, the initial position of the detector is determined by calculating the ROI position of the image by a formula when the angle between the reconstruction center and the rotation center is θ in a direction of 0 ° in the vertical direction.

3. The method according to claim 1, wherein in S20, the angle through which the swivel chair is rotated is set asThe range of the motion detector is [0,180 degrees+2Y ], Y is the corresponding fan-shaped angle under the maximum stroke, and the motion position of the detector can be calculated through a formula.

4. The method of claim 1, wherein in S50, the rotation of the seat is continued to be completed at a fixed angle of 180 ° +2y.

5. The large field CT imaging modality of claim 1, wherein the weighting method comprises the steps of:

s4, in the step of: for the scanning data of different angles under the second height, the weighting of one angle can be completed when the data under one scanning angle is obtained, and when all the data are And (3) completing all scanning of the data under the angles, namely completing weighting of all angles, and obtaining a final vertical large-field imaging result.

6. A large field-of-view CT imaging apparatus comprising:

an X-ray source: an X-ray emitting assembly;

the detector comprises: located opposite the X-ray source for capturing X-rays passing through the scanned object;

a rotating mechanism: including mechanical structures for supporting and rotating the X-ray source and detector;

Positioning structure: comprises a patient seat, a jaw support and a dental support column, which are used for fixing and adjusting the position of a patient in the scanning process;

safety device: comprises a radiation shielding and emergency stop button structure, so as to ensure the safety of operators and patients;

The large-field CT imaging apparatus is for implementing the large-field CT imaging method as defined in any one of claims 1 to 5.

7. An electronic device, comprising:

a memory storing execution instructions; and

A processor executing the memory-stored execution instructions, causing the processor to perform the large field CT imaging method of any one of claims 1 to 5.

8. A readable storage medium having stored therein execution instructions which when executed by a processor are for implementing the large field CT imaging method of any one of claims 1 to 5.