A continuous angular tracking high-speed cone beam CT control method and device

Abstract

The application discloses a high-speed cone beam CT control method and device for continuous angle tracking, and the control method comprises the following steps: controlling a high-voltage generator to start a continuous exposure mode, and controlling a flat panel detector to start a continuous perspective mode; synchronously acquiring perspective image data with time stamps of the flat panel detector and angle data with time stamps of a CT rotating mechanism; determining integral angle intervals of each row according to the perspective image data and the angle data; performing back projection algorithm processing on perspective image data corresponding to the integral angle intervals of each row; and reconstructing to obtain cone beam CT images. The application adopts a mode of continuous exposure of a high-voltage generator and continuous perspective image acquisition of a flat panel detector, synchronously acquires relatively dense time-angle sequences, and performs preprocessing and back projection reconstruction on the cone beam CT reconstruction algorithm in units of rows, thereby removing the synchronous control logic required by pulse exposure, reducing or eliminating the frame interval of cone beam CT perspective images, improving the overall acquisition efficiency of the cone beam CT, and reducing the system complexity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cone beam CT imaging, in particular to a high-speed cone beam CT control method and device with continuous angle tracking. BACKGROUND

[0002] Cone beam CT is a technology of obtaining three-dimensional image of an object from a series of perspective images taken around the object according to the approximate projection model of CT principle. The technology is widely used in medical examination and industrial non-destructive testing.

[0003] The overall workflow of cone beam CT is divided into two parts: acquisition and reconstruction. The acquisition part includes angle acquisition of the rotating mechanism, X-ray exposure and acquisition of perspective images. In the existing cone beam CT system, the X-ray pulse exposure and the flat panel detector external trigger perspective image acquisition mode are generally used, wherein each frame of perspective image waits for the end of the pulse exposure process before reading and transmitting to the image reconstruction subsystem. This is because the process from X-ray pulse exposure to the formation of the corresponding pixel electric signal involves the accumulation and readout of the stored charge in the thin film transistor during the X-ray pulse exposure process, both of which require a certain time. The charge accumulation process corresponds to the X-ray dose received by the pixel between the previous readout and the next readout. If the charge is read during the exposure process without special control and reconstruction process, the amount of X-ray charge read out between different rows of acquired images will have an angle deviation, which is the angle difference of the rotating mechanism rotation within the time difference of reading different rows.

[0004] Therefore, the existing cone beam CT control system needs to synchronize the pulse exposure timing of the high-voltage generator with the image acquisition timing of the flat panel detector, see Figure 2As shown, the exposure time of the high-voltage generator is t1', and the time for the flat panel detector to read the perspective image is t3'. After the cone-beam CT controller receives the signal that the flat panel detector has finished reading, the high-voltage generator starts the next exposure. Therefore, the cone-beam CT controller needs to be synchronized during the period from receiving the signal that the reading has finished to sending the signal that the exposure starts to the high-voltage generator, and during the period from receiving the signal that the exposure has finished to sending the signal that the reading starts to the flat panel detector. In this exposure and imaging process, the exposure angle corresponding to each perspective image is uniform, so the reconstruction algorithm of the existing cone-beam CT is used to pre-process and back-project the image in units of perspective images to obtain the overall cone-beam CT image. However, because synchronization is needed during the period from the end of the exposure of the high-voltage generator to the start of the reading of the flat panel detector, and during the period from the end of the reading of the flat panel detector to the start of the next exposure of the high-voltage generator, the cone-beam CT controller will have a certain time delay t2' during the synchronization process. During the time delay t2', the cone-beam CT is in a suspended state, so there will be a frame interval of the cone-beam CT perspective image, resulting in invalid time during the cone-beam CT irradiation process and reducing the overall acquisition efficiency of the cone-beam CT. Moreover, the control logic of the cone-beam CT is relatively complex, increasing the complexity of the system.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application provides a continuous-angle-tracking high-speed cone-beam CT control method and device, which solves the problem of time delay caused by the synchronization control logic required by pulse exposure, reduces or eliminates the frame interval of the cone-beam CT perspective image without increasing the dose of the subject, improves the overall acquisition efficiency of the cone-beam CT, and reduces the complexity of the system. Specifically, the following technical solutions are adopted:

[0007] A continuous-angle-tracking high-speed cone-beam CT control method, comprising

[0008] controlling the high-voltage generator to start a continuous exposure mode and controlling the flat panel detector to start a continuous perspective mode;

[0009] synchronously acquiring perspective image data with a time stamp from the flat panel detector and angle data with a time stamp from the CT rotating mechanism;

[0010] determining the integral angle interval of each row according to the perspective image data and the angle data, performing back-projection algorithm processing on the perspective image data corresponding to the integral angle interval of each row, and reconstructing to obtain a cone-beam CT image.

[0011] As an optional embodiment of the present invention, in a high-speed cone-beam CT control method with continuous angle tracking, the acquisition of fluoroscopic image data of the flat panel detector with timestamps includes: acquiring the fluoroscopic image row sequence [(L1,t1),(L1,t2),…,(L1,t2),…,(L1,t3)] of the flat panel detector during the operation of the high-speed cone-beam CT. M1 )], [(L2,t1),(L2,t2),…,(L2,t M2 )]、…、[(L n ,t1),(L n ,t2),…,(L n ,t Mn )];

[0012] The acquisition of time-stamped angle data of the CT rotation mechanism includes: acquiring angle sequences of the CT rotation mechanism [(A1,t1),(A2,t2),…, ... N ,t N )).

[0013] As an optional embodiment of the present invention, in a high-speed cone-beam CT control method with continuous angle tracking, the step of determining the integral angle interval of each row based on the fluoroscopic image data and angle data, and performing back-projection algorithm processing on the fluoroscopic image data corresponding to the integral angle interval of each row to reconstruct the cone-beam CT image includes:

[0014] The timestamp interval of each row is determined line by line based on the perspective image row sequence;

[0015] Based on the timestamp interval of each row, the angle interval corresponding to each row is obtained from the angle sequence of the CT rotating mechanism to obtain the integral angle of each row of the fluoroscopic image data.

[0016] For the fluoroscopic image row sequence, a back-projection algorithm is used to process the image row by row based on the integral angle of each row, and cone-beam CT images are reconstructed row by row.

[0017] As an optional embodiment of the present invention, in a high-speed cone-beam CT control method with continuous angle tracking, the acquisition of fluoroscopic image data of the flat panel detector containing timestamps includes: acquiring the fluoroscopic image frame sequence of the flat panel detector [(P1,t1),(P2,t2),…,(P...] during the operation of the high-speed cone-beam CT. M ,t M )];

[0018] The acquisition of time-stamped angle data of the CT rotating mechanism includes: acquiring angle sequences of the CT rotating mechanism [(A1,t1),(A2,t2),…, ... N ,tN )].

[0019] As an optional embodiment of the application, in the continuous angle tracking high-speed cone beam CT control method, the integral angle interval of each row is determined according to the perspective image data and the angle data, the perspective image data corresponding to the integral angle interval of each row is processed by the back projection algorithm, and the cone beam CT image is reconstructed.

[0020] For a perspective view P i , the perspective view P i-1 is obtained by interpolation according to the time stamps (t i , t readout ) of the previous frame and the current frame perspective view and the readout time length T i of the perspective view.The readout time of the first row of the previous frame is t , and the readout time of the current frame is t

[0021] The corresponding angle is obtained by interpolation from the angle sequence with time stamps. The corresponding angle is obtained by interpolation from the angle sequence with time stamps. The corresponding angle is obtained by interpolation from the angle sequence with time stamps. The angle interval is the integral angle interval of the first row. The corresponding angle is obtained by interpolation from the angle sequence with time stamps.

[0022] The perspective image row sequence is processed by the back projection algorithm based on the integral angle of each row, and the cone beam CT image is reconstructed row by row.

[0023] As an optional embodiment of the application, in the continuous angle tracking high-speed cone beam CT control method, the perspective view P i is obtained by interpolation according to the readout time of the first row of the previous frame t and the readout time of the current frame t

[0024] As an optional embodiment of the application, in the continuous angle tracking high-speed cone beam CT control method, the perspective image data with time stamps obtained by the flat panel detector is preprocessed, the perspective images of the first N frames in the perspective image data are discarded, or the perspective images in the initial time interval T are discarded, and the N and T are set values, and the N and T are obtained by actual test.

[0025] The application also provides a continuous angle tracking high-speed cone beam CT control device for implementing the high-speed cone beam CT control method, which comprises:

[0026] The cone beam CT control subsystem controls the high voltage generator to start the continuous exposure mode, controls the flat panel detector to start the continuous perspective mode, and controls the CT rotating mechanism to rotate and synchronously acquire the angle data of the CT rotating mechanism containing time stamps;

[0027] The CT image processing subsystem synchronously acquires the perspective image data of the flat panel detector containing time stamps, and receives the angle data of the CT rotating mechanism containing time stamps sent by the cone beam CT control subsystem.

[0028] The CT image processing subsystem determines the integral angle interval of each row according to the perspective image data and the angle data, performs the back projection algorithm processing on the perspective image data corresponding to the integral angle interval of each row, and reconstructs to obtain the cone beam CT image.

[0029] As an optional embodiment of the application, the CT control subsystem is connected with the communication interfaces of the CT rotating mechanism, the high voltage generator, the flat panel detector and the CT image processing subsystem, respectively, to obtain the angle of the CT rotating mechanism in real time and synchronize the time with the flat panel detector and the CT image processing subsystem.

[0030] As an optional embodiment of the application, the cone beam CT image processing subsystem is connected with the communication interfaces of the CT control subsystem and the flat panel detector, respectively.

[0031] The cone beam CT image processing subsystem receives the angle data containing time stamps acquired by the CT control subsystem, continuously receives the perspective image by the flat panel detector, executes the cone beam CT reconstruction algorithm, and outputs the reconstructed three-dimensional cone beam CT image.

[0032] Compared with the prior art, the application has the following beneficial effects:

[0033] The continuous angle tracking high-speed cone beam CT control method of the application adopts the high voltage generator X-ray continuous exposure and the flat panel detector continuous trigger perspective sampling mode, and improves the reconstruction process of the cone beam CT for such a sampling mode, so that the rotation time can be more fully utilized for uniform X-ray exposure, and the synchronization time delay between the CT controller control exposure pulse process and the flat panel detector sampling process is eliminated.

[0034] In addition, since the high-voltage generator adopts uninterrupted exposure, complete 360° projection data can be obtained in one exposure, the synchronization control logic required by pulse exposure is removed, the cone beam CT perspective frame interval can be reduced or eliminated without increasing the dose of the subject, the overall acquisition efficiency of the cone beam CT is improved, and the system complexity is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 A system block diagram of a continuous angle tracking high-speed cone beam CT control device according to an embodiment of the present application;

[0036] Figure 2 A timing diagram of the pulse exposure mode in the background art;

[0037] Figure 3 A control timing diagram of a continuous angle tracking high-speed cone beam CT control method according to an embodiment of the present application;

[0038] Figure 4 A diagram showing the relationship between each projection image and the actual rotation position under the pulse exposure mode of the existing cone beam CT processing system;

[0039] Figure 5 A diagram showing that each row of each projection image is rotated in turn to represent the actual projection position according to the continuous angle tracking high-speed cone beam CT control method of the present application. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application.

[0041] Therefore, the detailed description of the embodiments of the present application below is not intended to limit the scope of the claimed present application, but only represents some embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0042] It should be noted that the embodiments in the present application and the features and technical solutions in the embodiments can be combined with each other without conflict.

[0043] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0044] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0045] The continuous angle tracking high-speed cone beam CT control method of the embodiment comprises:

[0046] The high-voltage generator is controlled to start a continuous exposure mode, and the flat panel detector is controlled to start a continuous fluoroscopy mode.

[0047] Synchronously acquire fluoroscopy image data with time stamps of the flat panel detector and angle data with time stamps of the CT rotating mechanism.

[0048] According to the fluoroscopy image data and the angle data, the integral angle interval of each row is determined row by row, the fluoroscopy image data corresponding to the integral angle interval of each row is processed by back projection algorithm, and the cone beam CT image is reconstructed.

[0049] The continuous angle tracking high-speed cone beam CT control method of the embodiment adopts the high-voltage generator X-ray continuous exposure and the flat panel detector continuous trigger fluoroscopy mode, and improves the reconstruction process of the cone beam CT for such a mode. Thus, the uniform X-ray exposure can be more fully utilized in the rotation time, and the synchronization time delay t2' between the CT controller control exposure pulse process and the flat panel detector image acquisition process is eliminated. Referring to Figure 3 The timing diagram of the continuous angle tracking high-speed cone beam CT control method of the embodiment is shown. Since the high-voltage generator continuous exposure time t1 and the flat panel detector image acquisition time t2 overlap, the image acquisition time of each frame is only the readout time of the flat panel detector, only the exposure start includes communication delays t2-1 and t2-2, and the exposure end includes communication delays. A higher frame rate can be achieved in the same time, and the overall cone beam CT acquisition time can be shortened by 1 / 4 to 1 / 3.

[0050] In addition, since the high-voltage generator adopts uninterrupted exposure, complete 360° projection data can be obtained in one exposure, the synchronization control logic required by pulse exposure is removed, the cone beam CT fluoroscopy frame interval can be reduced or eliminated without increasing the dose of the subject, the overall acquisition efficiency of the cone beam CT is improved, and the system complexity is reduced.

[0051] The continuous angle tracking high-speed cone beam CT control method of the embodiment is divided into two stages of perspective image acquisition and three-dimensional cone beam CT image reconstruction, wherein the cone beam CT reconstruction stage can be executed offline or online, wherein offline execution refers to executing the reconstruction step after all perspective images are acquired, and online execution refers to projecting the perspective image onto the currently reconstructed three-dimensional cone beam CT image after each perspective image is acquired. In actual application, the reconstruction is generally executed online to form an initial cone beam CT image, and then the three-dimensional cone beam CT image with higher quality is reconstructed offline based on the image.

[0052] In the continuous angle tracking high-speed cone beam CT control method of the embodiment, the perspective image acquisition process is as follows:

[0053] The perspective image data with time stamps of the flat panel detector in the embodiment includes: acquiring perspective image row sequences [(L1, t1), (L1, t2), …, (L1, t M1 )] of the flat panel detector during the running of the high-speed cone beam CT, [(L2, t1), (L2, t2), …, (L2, t M2 )], …, [(L n ,t1),(L n ,t2),…,(L n ,t Mn )] of the flat panel detector.

[0054] The angle data with time stamps of the CT rotating mechanism in the embodiment includes: acquiring angle sequences [(A1, t1), (A2, t2), …, (A N ,t N )] of the CT rotating mechanism at an angle acquisition frequency higher than the perspective acquisition frequency of the flat panel detector.

[0055] Correspondingly, in the continuous angle tracking high-speed cone beam CT control method of the embodiment, the three-dimensional cone beam CT image reconstruction process is as follows:

[0056] The three-dimensional cone beam CT image reconstruction process of the embodiment includes: determining the integral angle interval of each row according to the perspective image data and the angle data, performing the back projection algorithm processing on the perspective image data corresponding to the integral angle interval of each row, and reconstructing the cone beam CT image.

[0057] The time stamp interval of each row is determined based on the perspective image row sequence;

[0058] According to the time stamp interval of each row, the angle interval corresponding to each row is acquired from the angle sequence of the CT rotating mechanism, and the integral angle of each row of the perspective image data is obtained.

[0059] For the fluoroscopic image row sequence, a back-projection algorithm is used to process the image row by row based on the integral angle of each row, and cone-beam CT images are reconstructed row by row.

[0060] In this embodiment, the fluoroscopic image acquisition and 3D cone-beam CT image reconstruction stages utilize a flat panel detector to directly read and record fluoroscopic image data line by line. Similarly, in the 3D cone-beam CT image reconstruction stage, the corresponding integration angle is determined line by line based on the timestamp. However, in existing cone-beam CT systems, flat panel detectors typically read fluoroscopic image data frame by frame. To achieve 3D cone-beam CT image reconstruction, the implementation process of a high-speed cone-beam CT control method with continuous angle tracking in this embodiment is as follows:

[0061] Fluoroscopy image acquisition process: Acquiring fluoroscopy image data with timestamps from the flat panel detector includes: acquiring the fluoroscopy image frame sequence [(P1,t1),(P2,t2),…,(P] from the flat panel detector during high-speed cone-beam CT operation. M ,t M The acquisition of time-stamped angle data of the CT rotating mechanism includes: acquiring angle sequences of the CT rotating mechanism at a higher angle acquisition frequency than that of the flat panel detector fluoroscopic acquisition frequency [(A1,t1),(A2,t2),…,(A...]; N ,t N )).

[0062] The 3D cone-beam CT image reconstruction process is as follows: Based on the fluoroscopic image data and angle data, the integral angle interval of each row is determined row by row. A back-projection algorithm is then performed on the fluoroscopic image data corresponding to the integral angle interval of each row to reconstruct the cone-beam CT image, including: for a perspective view P in the fluoroscopic image frame sequence... i Based on the timestamps of the previous and current frame perspectives (t... i-1 ,t i ) and the reading time T of the perspective view readout Interpolation to obtain perspective view P i Reading time of the frame preceding line l and current frame read time Obtained from sequence interpolation with timestamps corresponding angle and corresponding angle Then the angle range The integral angle interval of the l-th row is defined. For the fluoroscopic image row sequence, a back-projection algorithm is performed based on the integral angle of each row to reconstruct the cone-beam CT image row by row.

[0063] Specifically, interpolation is used to obtain the perspective view P. i Reading time of the frame preceding line l and the current frame read image time

[0064] The continuous angle tracking high-speed cone beam CT control method of the embodiment is used for pre-processing the perspective image data with time stamps of the flat panel detector, discarding perspective images of the first N frames in the perspective image data, or discarding perspective images in the initial time interval T, wherein N and T are set values, and N and T are obtained through actual tests.

[0065] The embodiment is used for performing back projection algorithm processing on the perspective image row sequence in units of rows based on integral angles of the rows, and reconstructing the cone beam CT image row by row.

[0066] Referring to Figure 4 As shown in the figure, when the existing cone beam CT system performs back projection algorithm, each projection image S' and the actual position relationship of rotation are shown in the figure. Since the high-voltage generator of the existing cone beam CT system is pulse exposure, and the CT rotation mechanism keeps the angle unchanged during each pulse exposure process, each projection image S' obtained by back projection reconstruction is in the same plane at the same angle. Figure 5 As shown in the figure, when the cone beam CT system of the embodiment performs back projection algorithm, each projection image S and the actual position relationship of rotation are shown in the figure. Since the high-voltage generator of the existing cone beam CT system is continuous pulse during the rotation of the CT rotation mechanism, and the flat panel detector is continuous perspective, the embodiment is reconstructed by row when performing back projection reconstruction. Each row on each projection image S has an angle deviation, and therefore is not in the same plane, but has no effect on the generation result of the final three-dimensional CT image. Only the process of back projection reconstruction is different.

[0067] Referring to Figure 1 As shown in the figure, the embodiment simultaneously provides a high-speed cone beam CT control device for implementing the continuous angle tracking high-speed cone beam CT control method, comprising:

[0068] The cone beam CT control subsystem 5 controls the high-voltage generator 2 to start the continuous exposure mode, controls the flat panel detector 3 to start the continuous perspective mode, and controls the CT rotation mechanism 1 to rotate and synchronously acquire angle data of the CT rotation mechanism with time stamps;

[0069] The CT image processing subsystem 4 synchronously acquires perspective image data of the flat panel detector 3 with time stamps, and receives angle data of the CT rotation mechanism 1 with time stamps sent by the cone beam CT control subsystem 5;

[0070] The CT image processing subsystem 4 determines the integral angle interval of each row according to the perspective image data and angle data, performs back projection algorithm processing on the perspective image data corresponding to the integral angle interval of each row, and reconstructs to obtain the cone beam CT image.

[0071] The continuous angle tracking high-speed cone beam CT control device of the embodiment adopts the high-voltage generator X-ray continuous exposure and the flat panel detector continuous trigger perspective image acquisition mode, and improves the cone beam CT reconstruction process for such an image acquisition mode, so that the uniform X-ray exposure can be more fully utilized in the rotation time, and the synchronization time delay t2' between the CT controller control exposure pulse process and the flat panel detector image acquisition process is eliminated. Referring to Figure 3 As shown in the timing diagram of the continuous angle tracking high-speed cone beam CT control device of the embodiment, because the high-voltage generator continuous exposure time t1 and the flat panel detector image acquisition time t2 overlap, the image acquisition time of each frame is only the readout time of the flat panel detector, only the exposure start includes communication delays t2-1 and t2-2, and the exposure end includes communication delays, a higher frame rate can be achieved in the same time, and the overall cone beam CT acquisition time can be shortened by 1 / 4 to 1 / 3.

[0072] In addition, because the high-voltage generator adopts uninterrupted exposure, complete 360° projection data can be obtained in one exposure, the synchronization control logic required by pulse exposure is removed, the cone beam CT perspective view frame interval can be reduced or eliminated without increasing the dose of the subject, the overall cone beam CT acquisition efficiency is improved, and the system complexity is reduced.

[0073] Further, the CT control subsystem 5 is connected with the communication interfaces of the CT rotating mechanism 1, the high-voltage generator 2, the flat panel detector 3, and the CT image processing subsystem 4 respectively, and obtains the angle of the CT rotating mechanism 1 in real time and synchronizes the time with the flat panel detector 3 and the CT image processing subsystem 4. It is required that the row direction of the flat panel detector is perpendicular to the rotation axis of the cone beam CT rotating mechanism.

[0074] Further, the cone beam CT image processing subsystem 4 is connected with the communication interfaces of the CT control subsystem 5 and the flat panel detector 3 respectively.

[0075] The cone beam CT image processing subsystem 4 receives the angle data with time stamp acquired by the CT control subsystem 5, continuously receives the perspective image through the flat panel detector 3, executes the cone beam CT reconstruction algorithm, and outputs the reconstructed three-dimensional cone beam CT image.

[0076] The continuous angle tracking high-speed cone beam CT control device of the embodiment, the perspective image acquisition execution process is as follows:

[0077] The cone-beam CT control subsystem 5, the cone-beam CT image processing subsystem 4, and the flat panel detector 3 communicate and synchronize their time information. This synchronization process can be completed based on a synchronization mechanism using technologies such as CAN bus, and the time of each subsystem is consistent after completion.

[0078] The high-voltage generator 2 is set to continuous uniform exposure mode, and the flat panel detector 3 is set to continuous fluoroscopy mode. The cone-beam CT control subsystem 5 sends exposure parameters to the high-voltage generator 2 through the communication interface with the high-voltage generator 2, and starts the continuous exposure of the high-voltage generator 2 through communication commands. If the flat panel detector 3 has only one communication interface, the cone-beam CT control subsystem 5 informs the cone-beam CT image processing subsystem 4 that exposure has started through the communication interface with the cone-beam CT image processing subsystem 4. The cone-beam CT image processing subsystem 4 starts the continuous fluoroscopy mode of the flat panel detector 3 through communication commands and starts receiving the fluoroscopic images transmitted back by the flat panel detector 3. In these fluoroscopic image sequences, since the exposure time of the first frame is unknown, it is difficult to process this frame and preprocess the subsequent frames. It is necessary to discard the first N frames of images. N is obtained through actual testing based on the specific system.

[0079] The cone-beam CT control subsystem 5 acquires the angular velocity and angle information of the CT rotation mechanism 1 at a higher rate than that acquired during fluoroscopy by the flat panel detector 3. After adding a timestamp, the information is sent to the cone-beam CT image processing subsystem 4. Since the amount of angle data is relatively small, as much angle information as possible can be acquired based on the system's communication bandwidth and the processing capability of the cone-beam CT control subsystem 5, so as to calculate more accurate angle data during the reconstruction stage.

[0080] The cone-beam CT image processing subsystem 4 synchronously acquires time-stamped fluoroscopic image frames and time-stamped angular velocity and angle information from the flat panel detector 3, and saves the image frame sequence obtained during the acquisition process [(P1,t1),(P2,t2),…,(P...]. M ,t M )] and angle sequence [(A1,t1),(A2,t2),…,(A N ,t N [For use in cone-beam CT reconstruction]

[0081] This embodiment provides a high-speed cone-beam CT control device with continuous angle tracking. The cone-beam CT reconstruction process of the cone-beam CT image processing subsystem 4 includes:

[0082] Suppose a perspective view has L rows. For a frame of perspective view P... i Based on the timestamps of the perspective views of the two frames before and after (t) i-1 ,t i ) and the reading time T of the perspective view readout Interpolation is used to obtain the reading time of the frame preceding the l-th row of the perspective view. and current frame read time Further, the angle interval is obtained from the time-stamped angular sequence interpolation The corresponding angle And Then the angle interval Is the integral angle of this row;

[0083] In the unit of perspective image, the image data is pre-processed and back-projected, and the cone-beam CT reconstruction considering the accurate integral angle is performed.

[0084] A continuous angle tracking high-speed cone-beam CT control device of the embodiment:

[0085] 1. According to the needs of specific products, the cone-beam CT hardware is designed, which includes a tube and a flat panel detector supporting mechanism that can rotate around an axis. After the tube and the flat panel detector are mounted, the row direction of the flat panel detector is perpendicular to the rotation axis, the column direction of the flat panel detector is parallel to the rotation axis, the minimum distance between the central vertical line of the tube and the central vertical line of the flat panel detector is less than 5mm, and the transformation range of the minimum distance during the rotation around the axis is less than 1mm, wherein the rotation mechanism axis drives the encoder to rotate through a gear.

[0086] 2. The cone-beam CT controller is realized based on a microprocessor, a printed circuit board, etc. The controller contains a serial communication interface with a high-voltage generator, a pulse communication interface with the high-voltage generator, a pulse signal interface with the flat panel detector, and a network interface (TCP / IP protocol) connected with the cone-beam CT image processing subsystem.

[0087] 3. The cone-beam CT controller control software is written, and multiple synchronous tasks are realized based on a real-time operating system. The main two tasks are as follows:

[0088] a) The Ethernet control RPC server task receives the RPC instructions transmitted by the cone-beam CT image processing subsystem through Ethernet, and performs flat panel detector state query, flat panel detector calibration, flat panel detector start perspective mode, tube parameter setting, tube state query, tube continuous exposure, etc. according to the instruction information.

[0089] b) The high-voltage generator serial command interface receives the high-voltage generator serial message and updates the high-voltage generator state.

[0090] 4. The cone-beam CT image processing subsystem software is written, which realizes the communication function of continuous exposure perspective and the algorithm of independent calculation of angle information and independent back-projection of each row, and realizes the back-projection algorithm of continuous tracking of each row angle.

[0091] The embodiment also provides a computer readable storage medium, which stores a computer executable program. The computer executable program is executed to implement the continuous angle tracking high-speed cone beam CT control method.

[0092] The computer readable storage medium in the embodiment can include a data signal propagating in a baseband or as a part of a carrier wave propagating in a baseband, which bears the readable program code. The propagating data signal can adopt multiple forms, including but not limited to an electromagnetic signal, an optical signal or any suitable combination of the above. The computer readable storage medium can also be any readable medium other than the readable storage medium, which can send, propagate or transmit the program for use by or in combination with an instruction execution system, device or apparatus. The program code contained in the computer readable storage medium can be transmitted by any suitable medium, including but not limited to wireless, wired, optical cable, RF and the like, or any suitable combination of the above.

[0093] The embodiment also provides an electronic device, which includes a processor and a memory. The memory is configured to store a computer executable program. When the computer program is executed by the processor, the processor executes the continuous angle tracking high-speed cone beam CT control method.

[0094] The electronic device can be in the form of a general computing device. The processor can be one or multiple and work cooperatively. The present application also does not exclude distributed processing, i.e. the processor can be dispersed in different physical devices. The electronic device of the present application is not limited to a single physical entity, but can also be the sum of multiple physical entities.

[0095] The memory stores a computer executable program, which is usually machine readable code. The computer readable program can be executed by the processor to enable the electronic device to execute the method of the present application or at least part of the steps in the method.

[0096] The memory includes a volatile memory, such as a random access memory (RAM) and / or a cache memory, and / or a non-volatile memory, such as a read only memory (ROM).

[0097] It should be understood that the electronic device of the present application can also include elements or components not shown in the above examples. For example, some electronic devices also include a display unit, such as a display screen, and some electronic devices also include human-computer interaction elements, such as buttons and keyboards. As long as the electronic device can execute the computer readable program in the memory to implement the method of the present application or at least part of the steps in the method, it can be considered as the electronic device covered by the present application.

[0098] Through the above description of the embodiments, those skilled in the art can easily understand that the present application can be implemented by hardware capable of executing a specific computer program, such as a system of the present application and an electronic processing unit, a server, a client, a mobile phone, a control unit, a processor, etc. contained in the system. The present application can also be implemented by computer software for executing the method of the present application, such as control software executed by a microprocessor, an electronic control unit, a client, a server, etc. However, it should be noted that the computer software for executing the method of the present application is not limited to being executed by one or a specific hardware entity, but can also be implemented in a distributed manner without specific hardware. For computer software, the software product can be stored in a computer-readable storage medium (which can be a CD-ROM, a U disk, a mobile hard disk, etc.), or can be distributed on a network, as long as it can make electronic equipment execute the method according to the present application.

[0099] The above embodiments are only used to illustrate the present application and not to limit the technical solutions described in the present application. Although the present application has been described in detail with reference to the above embodiments, the present application is not limited to the above specific embodiments, and any modification or equivalent replacement of the present application; all technical solutions and improvements that do not deviate from the spirit and scope of the present application are encompassed in the scope of the claims of the present application.

Claims

1. A continuous angular tracking high-speed cone beam CT control method, characterized by, The application relates to a cone-beam CT image reconstruction method and device. The high-voltage generator is started in a continuous exposure mode, and the flat panel detector is started in a continuous perspective mode; Synchronously acquiring perspective image data with time stamps of the flat panel detector and angle data with time stamps of the CT rotating mechanism; According to the perspective image data and the angle data, integral angle intervals of each row are determined, and the perspective image data corresponding to the integral angle intervals of each row is processed by back projection algorithm to reconstruct a cone-beam CT image; The acquisition of the perspective image data with time stamps of the flat panel detector comprises: Acquisition of fluoroscopic image sequence [(L1,t1),(L1,t2),…,(L1,t2)] from a flat-panel detector during high-speed cone-beam CT operation M1 )], [(L2,t1),(L2,t2),…,(L2,t M2 )]、…、[(L n ,t1),(L n ,t2),…,(L n ,t Mn )]; Acquisition of fluoroscopic image frame sequences from a flat-panel detector during high-speed cone-beam CT operation [(P1,t1),(P2,t2),…,(P M ,t M )]; The acquisition of the angle data of the CT rotating mechanism containing the time stamp comprises: acquiring an angle sequence [(A1, t1), (A2, t2), …, (A N ,t N )] of the CT rotating mechanism at an angle acquisition frequency higher than a flat panel detector perspective acquisition frequency. The acquisition of the perspective image data with time stamps of the flat panel detector comprises: According to the time stamp intervals of each row, corresponding angle intervals of each row are acquired in the angle sequence of the CT rotating mechanism to obtain integral angles of each row of the perspective image data; According to the time stamp intervals of each row, corresponding angle intervals of each row are acquired in the angle sequence of the CT rotating mechanism to obtain integral angles of each row of the perspective image data; For a frame perspective P of the sequence of perspective video frames i , the perspective P is interpolated from the timestamps (t i-1 , t i ) of the previous and current frame perspective and the readout duration T readout of the perspective P i The readout time of the previous frame and the readout time of the current frame obtained from the angular sequence interpolation with time stamp the corresponding angle and the corresponding angle then the angular interval is the integral angular interval for the l-th row; The cone-beam CT image is reconstructed row by row by back projection algorithm based on the integral angles of each row.

2. The control method of a continuous angular tracking high-speed cone beam CT according to claim 1, characterized in that, The perspective view P is obtained by interpolation i The read picture time of the previous frame and the read picture time of the current frame 3. The control method of a continuous angular tracking high-speed cone beam CT according to any one of claims 1-2, characterized in that, The application further relates to a cone-beam CT image reconstruction device. The application further relates to a cone-beam CT image reconstruction device.

4. A high-speed cone beam CT control device for realizing the continuous angle tracking of the high-speed cone beam CT control method according to any one of claims 1 to 3, characterized by The cone-beam CT control subsystem controls the high-voltage generator to start the continuous exposure mode, controls the flat panel detector to start the continuous perspective mode, and controls the CT rotating mechanism to rotate and synchronously acquire angle data with time stamps of the CT rotating mechanism; The CT image processing subsystem synchronously acquires perspective image data with time stamps of the flat panel detector and receives the angle data with time stamps of the CT rotating mechanism sent by the cone-beam CT control subsystem; The CT image processing subsystem determines integral angle intervals of each row according to the perspective image data and the angle data, processes the perspective image data corresponding to the integral angle intervals of each row by back projection algorithm, and reconstructs a cone-beam CT image. The CT control subsystem is connected with communication interfaces of the CT rotating mechanism, the high-voltage generator, the flat panel detector and the CT image processing subsystem respectively, and can acquire the angle of the CT rotating mechanism in real time and synchronize time with the flat panel detector and the CT image processing subsystem.

5. The control device for a continuous angular tracking high-speed cone beam CT according to claim 4, wherein The CT image processing subsystem is connected with the CT control subsystem and the flat panel detector respectively; 6. The control device for a continuous angular tracking high-speed cone beam CT according to claim 4, wherein The CT image processing subsystem receives the angle data with time stamps acquired by the CT control subsystem, continuously receives perspective images through the flat panel detector, executes a cone-beam CT reconstruction algorithm, and outputs a reconstructed three-dimensional cone-beam CT image. ​

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