Guided puncture method, rapid low-dose CT-guided puncture method, and three-source computed tomography system

Abstract

A guided puncture method, a rapid low-dose CT-guided puncture method, and a three-source computed tomography system. The guided puncture method comprises: in a three-source computed tomography (CT) system, performing full scanning or half scanning, so as to obtain a first image, wherein the first image corresponds to a puncture needle being located at a position different from a first position; on the basis of the first image, determining a plurality of second images in an image domain, wherein the second images correspond to the puncture needle being located at other positions; and determining the position of the puncture needle by using actual projection data of a three-source triple-detector at three preset angles, and the orthographic projections of the plurality of second images at the three angles.

Description

Guided puncture method, rapid low-dose CT-guided puncture method and three-source computed tomography system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on and claims priority to an application with CN application number 202311243175.0 and filing date September 25, 2023. The disclosure content of this CN application is hereby incorporated into this disclosure as a whole. Technical Field

[0003] The present disclosure relates to an application field of medical X-ray imaging equipment, specifically a guided puncture method, a rapid low-dose CT-guided puncture method, and a three-source computed tomography system. Background Art

[0004] CT (Computed Tomograph)-guided interventional surgery is an effective percutaneous non-vascular interventional technique, including CT-guided percutaneous biopsy and interventional treatment, which can be used in various parts of the body, including the head, chest, abdomen, and musculoskeletal system.

[0005] CT-guided interventional surgery can accurately locate the lesion site and clearly understand the soft tissue and blood vessels around the lesion. Therefore, the needle position, angle and depth can be accurately determined, and can be adjusted at any time under CT scanning monitoring, so precise puncture can be achieved.

[0006] CT-guided interventional surgery can also be combined with a "robot" to complete puncture planning through three-dimensional CT images and guide the robotic arm to complete the interventional surgery along the planned route.

[0007] Common CT-guided interventional procedures include: interventional treatment of neuralgia, puncture biopsy of lung nodules, drainage of abdominal or liver abscesses, etc.

[0008] Existing CT-guided puncture operations have problems such as slow scanning speed and high radiation dose to patients.

[0009] At present, CT-guided interventional operations have formed operating standards. The Interventional Minimally Invasive Professional Committee of the Chinese Medical Education Association and the Interventional Branch of the Chinese Medical Association jointly published the "CT-Guided Interventional Operation Standards 2022 Edition" (Journal of Medical Imaging, Volume 32, No. 3, 2022, Interventional Minimally Invasive Professional Committee of the Chinese Medical Education Association, Interventional Branch of the Chinese Medical Association).

[0010] In conventional single-source / dual-source CT, CT-guided interventional procedures typically utilize low-dose CT "fluoroscopy" (Fluoro) guidance. There are two main Fluoro scanning modes: intermittent exposure mode, in which each exposure completes a 360-degree full scan or a 180-degree + sector angle half scan, with needle insertion and exposure performed alternately; continuous exposure mode, in which the CT device continuously exposes and reconstructs images, allowing exposure and needle insertion to proceed simultaneously. However, both modes require at least 180-degree + sector angle exposure to obtain the current needle position. On the current fastest gantry rotation system (0.25s / rotation), an exposure of approximately 0.16s is required, which is relatively slow (not capable of real-time display) and results in a relatively high radiation dose. Summary of the Invention

[0011] In order to address the defects and shortcomings of the above-mentioned related technologies, the present disclosure provides a fast and low-dose CT-guided puncture method that can complete puncture guidance through a few scans and several pulse exposure data acquisitions, with fast feedback on the needle insertion status during the puncture process and greatly reduced radiation dose.

[0012] The technical solution adopted by the present disclosure to solve its technical problems is: a guided puncture method, comprising: performing a full scan or a half scan in a three-source computed tomography system to obtain a first image, wherein the first image corresponds to a puncture needle in a first position; based on the first image, determining multiple second images in an image domain, wherein the second images correspond to the puncture needle in positions other than the first position; and determining the position of the puncture needle by utilizing actual projection data of three sources and three detectors at three pre-set angles and the orthographic projections of the multiple second images at the three angles.

[0013] In some embodiments, determining multiple second images in the image domain based on the first image includes: determining the image of the puncture needle based on the first image; and gradually moving the puncture needle along the needle insertion direction in the image domain based on the image of the puncture needle and the first image to determine the multiple second images.

[0014] In some embodiments, determining the image of the puncture needle based on the first image includes: placing the patient in an appropriate body position and scanning position for scanning to obtain an original image that does not include the puncture needle; and obtaining the image of the puncture needle by subtracting the first image and the original image.

[0015] In some embodiments, the guided puncture method further includes: obtaining the direction of the puncture needle by a straight line detection method based on the image of the puncture needle, wherein the needle insertion direction is along the direction of the puncture needle and toward the patient's body.

[0016] In some embodiments, the position of the puncture needle is determined using the actual projection data of the three-source three-detector at three pre-set angles and the orthographic projections of the multiple second images at the three angles, including: for each second image, performing orthographic projection at three angles according to the geometric arrangement of the three-source computed tomography system and the three pre-set angles; subtracting the orthographic projection of each second image from the actual projection data at the corresponding angle to determine the difference between the orthographic projection of each second image and the actual projection data at the corresponding angle; among the multiple second images, determining the second image with the smallest sum of the absolute values ​​of the differences or the sum of the squares of the differences; and determining the position of the puncture needle based on the second image with the smallest sum of the absolute values ​​of the differences or the sum of the squares of the differences.

[0017] In some embodiments, determining the position of the puncture needle based on the second image in which the sum of the absolute values ​​of the differences or the sum of the squares of the differences is minimized includes: determining the position corresponding to the second image as the position of the puncture needle when the sum of the absolute values ​​of the differences or the sum of the squares of the differences corresponding to the second image is less than a threshold value; and re-executing the steps of obtaining the first image, determining multiple second images based on the first image, and determining the position of the puncture needle based on actual projection data and the forward projection of the multiple second images when the sum of the absolute values ​​of the differences or the sum of the squares of the differences corresponding to the second image is greater than or equal to the threshold value.

[0018] In some embodiments, the guided puncture method further includes: stopping the rotation of the gantry of the three-source computed tomography system so that the three tubes in the three-source computed tomography system stop at a preset angle, and performing exposure to collect actual projection data at three angles; or keeping the gantry of the three-source computed tomography system rotating, and performing exposure at three preset angles to collect actual projection data at three angles.

[0019] In some embodiments, the first position is a position where the depth of the puncture needle reaches a preset depth threshold.

[0020] In some embodiments, the full scan is a scan that exposes 360 degrees; and the half scan is a scan that exposes an angle that is the sum of the fan angle of the three-source three-detector and 180 degrees.

[0021] In some embodiments, gradually moving the puncture needle along the needle insertion direction in the image domain includes moving the puncture needle along the same straight line, and the movement interval on each coordinate axis is no greater than 1 / 2 pixel.

[0022] In some embodiments, the exposure is a pulsed exposure or an exposure controlled by milliampere modulation.

[0023] In some embodiments, the guided puncture method further includes: using two-dimensional data and performing verification using a numerical simulation method.

[0024] According to another aspect of the present disclosure, a fast and low-dose CT-guided puncture method is provided. In a three-source CT system, after completing a scan of one circle or 180 degrees + a fan angle, the projection data of the three sources and three detectors at three predetermined angles (gantry rotation or stationary) are used to calculate the change in the position of the puncture needle, and the reliability of the calculation result is confirmed by the degree of consistency between the orthographic projection of the three angles and the actual projection data. Thus, the puncture guidance can be completed with a small number of scans and several pulsed line-offs, with a fast scanning speed and a greatly reduced radiation dose.

[0025] In some embodiments, the specific implementation steps of the rapid low-dose CT-guided puncture method are as follows:

[0026] 1) Place the patient in the appropriate body position and scanning location to obtain raw data and images (Img0) without needle insertion;

[0027] 2) Insert the needle according to the pre-planned direction and path;

[0028] 3) After the needle is inserted (the needle is at a certain depth in the patient's body), a rotation method is used to collect data for one circle or 180 degrees + fan angle and reconstruct an image (Img1);

[0029] 4) By subtracting the image (Img1-Img0), the needle image Img can be obtained. needle ;

[0030] 5) The direction of the (straight) needle is obtained by a straight line detection method, and the needle insertion direction is along the direction of the needle into the patient's body;

[0031] 6) In the image domain, gradually move the needle along the insertion direction and keep it on the same straight line, with the interval on each coordinate axis not greater than 1 / 2 pixel, to form a series of image data ImgCN1…ImgCN n ;

[0032] 7) Stop the gantry rotation and stop the three tubes at a preset angle; or keep the gantry rotating and perform pulse exposure only at the preset angle;

[0033] 8) Pulse exposure as needed;

[0034] 9) Each pulse exposure collects projection data proj1 at three angles n ,proj2 n ,proj3 n ;

[0035] 10) For the data obtained in step 6, ImgCNx Perform orthographic projection in three directions according to the system geometry and the preset tube angle in step 7, and subtract the actual projection data of the corresponding angles obtained in steps 8 and 9;

[0036] 11) Calculate the difference, perform thresholding on the difference, calculate the absolute value and sum it, or sum of squares, and find the ImgCN with the smallest sum of the absolute value of the difference or the sum of the squares min If the absolute value and square sum of the corresponding differences are less than the threshold TH, it can be considered that the needle insertion depth and the image after needle insertion are consistent with ImgCN min Approximately, ImgCN min As the image shows after needle insertion;

[0037] 12) If ImgCN min If the absolute value sum or square sum of the corresponding differences is greater than the threshold TH, it is considered that the needle path is inconsistent with the expectation, such as the needle path has rotated or translated, or the patient has moved. In this case, the operator is prompted to perform a 360 full scan or half scan to obtain Img r ;

[0038] 13) Through the non-needle image Img0 and Img r Perform rigid registration (rotation + translation) to obtain a new non-needle image Img r0 , and continue to calculate and display the needle insertion process from step 4.

[0039] In some embodiments, in step 7), tube 1 is stopped at 0 degrees; tube 2 at 240 degrees; and tube 3 at 120 degrees. However, the angles of the three tubes at the time of stopping do not affect the feasibility of the method and can be any angle, but the spacing of the tubes is determined by the system's pre-design. Stopping the gantry rotation is not essential; pulse exposure at specific angles during rotation can achieve the same effect, with the interval between pulse exposures selected based on the required refresh rate.

[0040] In some embodiments, in step 8), if the X-ray source hardware does not support pulse exposure, a larger amplitude mA modulation may be used instead of pulse exposure to significantly reduce the dose.

[0041] In some embodiments, numerical simulation methods are used to verify the algorithm and processing flow of the method, which uses two-dimensional data, but the method itself is not limited to two-dimensional data.

[0042] According to yet another aspect of the present disclosure, a three-source computed tomography system is provided, configured to perform the guided puncture method described above or the fast low-dose CT-guided puncture method described above.

[0043] The present invention can complete puncture guidance through a few scans and several pulse line releases, has a fast scanning speed, can track the puncture needle insertion situation in real time, and greatly reduces the radiation dose. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a diagram showing the composition of a CT system used in the present disclosure;

[0045] FIG2A is a schematic diagram of a process flow of some embodiments of the present disclosure;

[0046] FIG2B is a flowchart of other embodiments of the present disclosure;

[0047] FIG3 is a schematic diagram of an XCAT digital phantom used in simulations of the present disclosure;

[0048] FIG4 is a schematic diagram of a needle used for simulating puncture of a high-density straight line segment according to the present invention;

[0049] FIG5 is an image of the present disclosure after needle insertion;

[0050] Figure 6 shows a series of images ImgCN obtained by moving the needle along the insertion direction. m A position in

[0051] FIG7 is a graph showing the sum of the absolute values ​​of the difference between a certain needle insertion depth and other positions according to the present disclosure;

[0052] FIG8 is a surface diagram showing the sum of the absolute values ​​of the three projection differences between all needle insertion positions of the present disclosure and other needle insertion positions;

[0053] FIG9 is a surface diagram showing the sum of the absolute values ​​of the differences in projections when the patient and the needle are rotated together by 0.5 degrees according to the present disclosure;

[0054] FIG10 is a surface diagram showing the sum of the absolute values ​​of the differences between the projections of the needle at various positions on the ideal needle insertion path when the needle is rotated 0.5 degrees deeper in the present disclosure;

[0055] FIG11 is a corresponding surface diagram when the needle is offset by one pixel from the ideal needle insertion path in the present disclosure;

[0056] FIG12 is an image after adding noise according to the present disclosure;

[0057] FIG13 is a schematic diagram showing a comparison before and after thresholding processing according to the present disclosure;

[0058] FIG14 is a three-dimensional surface diagram showing the differences in all needle insertion depths disclosed herein;

[0059] FIG15 is a schematic diagram of the present disclosure after thresholding and adding noise. DETAILED DESCRIPTION

[0060] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0061] As shown in Figure 1, in a three-source CT system, after completing a full scan (180 degrees plus a sector angle), the present invention uses projection data from three sources and three detectors at three pre-set angles (with the gantry rotating or stationary) to calculate the change in needle position. The reliability of the calculated result is confirmed by the degree of agreement between the orthographic projections from these three angles and the actual projection data. Therefore, the present device and method can complete a puncture procedure with a single scan and a few pulsed releases, resulting in faster scanning speeds and significantly reduced radiation dose.

[0062] First, a basic embodiment of the present disclosure will be described with reference to FIG2A . In some embodiments, a guided puncture method includes: step S1, performing a full scan or a half scan in a three-source computed tomography system to obtain a first image, wherein the first image corresponds to a puncture needle at a first position; step S2, determining, based on the first image, a plurality of second images in an image domain, wherein the second images correspond to the puncture needle at positions other than the first position; and step S3, determining the position of the puncture needle using actual projection data of the three-source, three-detector system at three pre-set angles and orthographic projections of the plurality of second images at the three pre-set angles.

[0063] Next, a specific embodiment of the guided puncture method proposed in the present disclosure will be described in conjunction with FIG2B . As shown in FIG2B , the specific implementation steps of the present disclosure are as follows:

[0064] 1) Place the patient in the appropriate body position and scanning location for scanning to obtain the original data and image (Img0) without the needle inserted. In other words, obtain the original image without the puncture needle.

[0065] 2) Insert the needle according to the pre-planned direction and path;

[0066] 3) After the needle is inserted (the needle is at a certain depth in the patient's body), a rotation method is used to collect data for one circle (180 degrees + fan angle) and reconstruct an image (Img1), i.e., the first image, which corresponds to the puncture needle at a certain depth in the patient's body;

[0067] 4) By subtracting the image (Img1-Img0), the needle image Img can be obtained. needle ;

[0068] 5) The direction of the (straight) needle is obtained by a straight line detection method, and the needle insertion direction is along the direction of the needle into the patient's body;

[0069] 6) In the image domain, gradually move the needle along the insertion direction and keep it on the same straight line, with the interval on each coordinate axis not greater than 1 / 2 pixel, to form a series of image data ImgCN1…ImgCN n , i.e., a second image, the second image corresponds to the puncture needle at another position;

[0070] 7) Stop the gantry rotation and stop the three tubes at a preset angle, or keep the gantry rotating and perform pulse exposure at a specific angle (e.g., tube 1 at 0 degrees; tube 2 at 240 degrees; tube 3 at 120 degrees);

[0071] 8) Pulse exposure on demand (if the X-ray source hardware does not support pulse exposure, a larger amplitude milliampere modulation can be used instead of pulse exposure to significantly reduce the dose, that is, the exposure is controlled by a larger amplitude milliampere modulation);

[0072] 9) Each pulse exposure collects actual projection data proj1 at three angles n ,proj2 n ,proj3 n ;

[0073] 10) For the data obtained in step (6) (multiple second images), each second image ImgCN x Perform orthographic projection in three directions according to the system geometry and the preset tube angle in step (7), and subtract the actual projection data of the corresponding angles obtained in steps 8 and 9;

[0074] 11) Calculate the difference, perform thresholding on the difference, calculate the absolute value and sum it, or sum of squares, and find the ImgCN with the smallest sum of the absolute value of the difference or the sum of the squares min If the absolute value and square sum of the corresponding differences are less than the threshold TH, it can be considered that the needle insertion depth and the image after needle insertion are consistent with ImgCN min Approximately. ImgCN min As the image after needle insertion is shown.

[0075] 12) If ImgCN min If the absolute value sum or square sum of the corresponding differences is greater than the threshold TH, it is considered that the needle path is inconsistent with the expectation, such as the needle path has rotated or translated, or the patient has moved. In this case, the operator is prompted to perform a 360 full scan or half scan to obtain Img r .

[0076] 13) Through the non-needle image Img0 and Img rPerform rigid registration (rotation + translation) to obtain a new non-needle image Img r0 , and continues to calculate and display the needle insertion process from step 4, including re-executing the three steps of obtaining the first image, determining multiple second images based on the first image, and determining the position of the puncture needle based on the actual projection data and the positive projection of the multiple second images.

[0077] In some embodiments, the present disclosure also proposes a three-source computed tomography (CT) system that can perform the guided puncture method described in any of the above embodiments. The puncture surgery can be completed through one scan and several pulsed radiographs, with fast scanning speed and greatly reduced radiation dose.

[0078] The present disclosure uses a numerical simulation method to verify the algorithm and processing flow as follows. The verification uses data from a single slice, but the method itself is not limited to single slice data.

[0079] The simulation uses a digital phantom, such as XCAT (see Figure 3);

[0080] As shown in FIG4 , the high-density straight line segment simulates the needle used for puncture;

[0081] The image after needle insertion is shown in Figure 5;

[0082] The needle moves along the insertion direction to obtain a series of images ImgCN m ,Figure 6 shows one of the locations.

[0083] The sum of the absolute values ​​of the differences between a particular needle insertion depth and other locations can be displayed as a curve (as shown in Figure 7); the sum of the absolute values ​​of the differences between all needle insertion locations and the three projections of other needle insertion locations can be displayed as a surface. Through overall data analysis, it can be found that regardless of the needle position, the needle insertion location and the corresponding composite image can be obtained by finding the minimum sum of the absolute values ​​of the differences between the three projections at that location and the three projections corresponding to each needle insertion depth.

[0084] In Figure 8, the x and y coordinates are the current needle position and the other needle positions, respectively, and z is the sum of the absolute values ​​of the differences between the three projections corresponding to the current needle position and the other needle positions. Figure 8 shows that, without considering noise, the sum of the absolute values ​​of the differences between the three projections corresponding to the orthographic projection of the synthetic image closest to the current needle position is approximately 0. The minimum value of the sum of the absolute values ​​of the differences between the orthographic projection of the synthetic image with a one-pixel difference and the three projections of the current position is 25.8;

[0085] When the patient and needle are rotated 0.5 degrees together, the minimum value of the sum of the absolute values ​​of the differences is still found for each needle insertion depth, but this minimum value is much larger than the sum of the absolute values ​​of the differences in projections when only the needle insertion depths differ. Figure 9 shows the surface of the sum of the absolute values ​​of the differences in projections when the patient and needle are rotated 0.5 degrees together. The minimum value of the sum of the absolute values ​​of the differences for all positions is 1131.8.

[0086] When the needle is rotated 0.5 degrees and not inserted according to the insertion path, the curve of the sum of the absolute values ​​of the differences between the projections at each position and the ideal insertion path is shown in Figure 10. The minimum sum of the absolute values ​​of the differences at all positions is 19.2.

[0087] When the needle is offset by one pixel from the ideal insertion path (since the insertion path is determined after the initial insertion, this should not occur in theory), the corresponding surface is shown in Figure 11. The minimum value of the sum of the absolute values ​​of the differences at the locations where the needle insertion depths most closely match (the locations where the sum of the absolute values ​​of the differences is the smallest) is 18.8.

[0088] When there is noise in the image, in order to simulate a lower dose, the SD (Standard Deviation) value is selected to be 20. The image after adding noise is shown in FIG12 .

[0089] In the presence of noise, if the noise is not processed, the sum of the absolute values ​​of the differences will be large. Therefore, the differences need to be thresholded. In this example, a threshold of 1.1 is selected (as shown in Figure 13), which can more perfectly filter out the noise without affecting the changes in the projection values ​​caused by the difference in needle position.

[0090] The differences in all needle insertion depths can also be displayed as a three-dimensional surface, as shown in Figure 14.

[0091] After thresholding, the minimum sum of the absolute differences between the projections of the needle insertion positions and the actual position in the image with added noise (sd = 20) is significantly lower than in the case of rotational or translational deviations, as shown in Figure 15. The minimum sum of the absolute differences across all positions is 0, and the maximum is 1.2. A threshold value TH between 1.2 and 18.8 allows tracking of the needle position when the patient or needle does not move, while indicating the completion of a 360-degree scan when the patient or needle does move.

[0092] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0093] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A guided puncture method, comprising: In a three-source computed tomography (CT) system, a full scan or a half scan is performed to obtain a first image, wherein the first image corresponds to the puncture needle being at a first position; Determine a plurality of second images in an image domain based on the first image, the second images corresponding to the puncture needle at other positions different from the first position; The position of the puncture needle is determined by using the actual projection data of the three sources and three detectors at three preset angles and the orthographic projections of the multiple second images at the three angles.

2. The guided puncture method according to claim 1, wherein: Determining a plurality of second images in an image domain according to the first image comprises: determining an image of the puncture needle according to the first image; According to the image of the puncture needle and the first image, the puncture needle is gradually moved along the needle insertion direction in the image domain to determine the plurality of second images.

3. The guided puncture method according to claim 2, wherein: Determining the image of the puncture needle according to the first image includes: Place the patient in the appropriate body position and scanning position for scanning to obtain the original image without the puncture needle; The image of the puncture needle is obtained by subtracting the first image from the original image.

4. The guided puncture method according to claim 2, further comprising: According to the image of the puncture needle, the direction of the puncture needle is obtained by a straight line detection method, wherein the needle insertion direction is along the direction of the puncture needle and toward the patient's body.

5. The guided puncture method according to claim 1, wherein: Determining the position of the puncture needle by using the actual projection data of the three sources and three detectors at three preset angles and the orthographic projections of the plurality of second images at the three angles comprises: For each second image, performing orthographic projection at three angles according to the geometric arrangement of the three-source computed tomography system and three preset angles; Subtracting the orthographic projection of each second image from the actual projection data at the corresponding angle to determine the difference between the orthographic projection of each second image and the actual projection data at the corresponding angle; Determine, among the plurality of second images, a second image having a minimum sum of absolute values ​​of the differences or a minimum sum of squares of the differences; The position of the puncture needle is determined according to the second image in which the sum of the absolute values ​​of the differences or the sum of the squares of the differences is the smallest.

6. The guided puncture method according to claim 5, wherein: Determining the position of the puncture needle according to the second image having the smallest sum of the absolute values ​​of the differences or the smallest sum of the squares of the differences comprises: When the sum of the absolute values ​​of the difference values ​​corresponding to the second image or the sum of the squares of the difference values ​​is less than a threshold value, determining the position corresponding to the second image as the position of the puncture needle; When the sum of the absolute values ​​of the differences corresponding to the second image or the sum of the squares of the differences is greater than or equal to a threshold, the first image is obtained again, a plurality of second images are determined based on the first image, and the position of the puncture needle is determined based on the actual projection data and the forward projection of the plurality of second images.

7. The guided puncture method according to claim 1, further comprising: Stopping the rotation of the rack of the three-source computed tomography system so that the three tubes in the three-source computed tomography system stop at a preset angle, and performing exposure to collect actual projection data at three angles; or The gantry of the three-source computed tomography system is kept rotating, and exposure is performed at certain specific angles to collect actual projection data at three angles.

8. The guided puncture method according to claim 1, wherein: The first position is the position when the depth of the puncture needle reaches a preset depth threshold.

9. The guided puncture method according to claim 1, wherein: The full scan is a scan with 360-degree exposure; The half scan is a scan of an angle that is the sum of the fan angle of the three-source three-detector exposure and 180 degrees.

10. The guided puncture method according to claim 2, wherein: Gradually moving the puncture needle along the needle insertion direction in the image domain includes moving the puncture needle along the same straight line, and the movement interval on each coordinate axis is no greater than 1 / 2 pixel.

11. The guided puncture method according to claim 7, wherein: The exposure is pulsed exposure or exposure controlled by mA modulation.

12. The guided puncture method according to claim 1, further comprising: Two-dimensional data are used to verify the results using numerical simulation methods.

13. A rapid low-dose CT-guided puncture method, characterized by: In the three-source CT system, after completing a scan of one circle or 180 degrees + fan angle, the projection data of the three sources and three detectors at three pre-set angles (gantry rotation or stationary) are used to calculate the change in the position of the puncture needle, and the degree of consistency between the three-angle orthographic projection and the actual projection data is used to confirm whether the calculation result is reliable. Therefore, the puncture guidance can be completed with one scan and several pulse releases, with fast scanning speed and greatly reduced radiation dose.

14. The rapid low-dose CT-guided puncture method according to claim 13, characterized in that: The specific implementation steps are as follows: 1) Place the patient in an appropriate position and scanning position to obtain raw data and images (Img0) without needle insertion; 2) Insert the needle according to the pre-planned direction and path; 3) After the needle is inserted (the needle is at a certain depth in the patient's body), a rotation method is used to collect one circle or 180 degrees + fan angle data and reconstruct the image (Img1); 4) By subtracting the image (Img1-Img0), the image of the needle Img can be obtained. needle ; 5) The direction of the (straight) needle is obtained by a straight line detection method, and the needle insertion direction is along the direction of the needle into the patient's body; 6) In the image domain, the needle is gradually moved along the insertion direction and kept on the same straight line, with the interval on each coordinate axis not greater than 1 / 2 pixel, to form a series of image data ImgCN1…ImgCN n ; 7) Stop the rack rotation and make the three tubes stop at a preset angle; or keep the rack rotating and expose and collect data at certain specific angles; 8) Pulse exposure on demand; 9) Each pulse exposure collects projection data of three angles corresponding to three sets of tube + detector combinations proj1 n ,proj2 n ,proj3 n ; 10) For the data obtained in step 6, ImgCN x Perform orthographic projection in three directions according to the system geometry and the preset tube angle in step 7, and subtract the actual projection data of the corresponding angles obtained in steps 8 and 9; 11) Calculate the difference, threshold the difference, calculate the absolute value and sum it, or the sum of squares, and find the ImgCN with the smallest sum of the absolute value of the difference or the sum of squares min If the absolute value and square sum of the corresponding differences are less than the threshold TH, it can be considered that the needle insertion depth and the image after needle insertion are consistent with ImgCN min Approximately, ImgCN min As the image shows after needle insertion; 12) If ImgCN min If the absolute value or square sum of the corresponding differences is greater than the threshold TH, it is considered that the needle path is inconsistent with the expectation, such as the needle path has rotated or translated, or the patient has moved. At this time, the operator is prompted to perform a 360 full scan or half scan to obtain Img r ; 13) Through the non-needle images Img0 and Img r Perform rigid registration (rotation + translation) to obtain a new image Img without needle insertion r0 , and continue to calculate and display the needle insertion process from step 4.

15. The rapid low-dose CT-guided puncture method according to claim 14, characterized in that: In step 7), the positions of ball tube 1, ball tube 2, and ball tube 3 are known, and the arrangement of the multiple ball tubes is known.

16. The rapid low-dose CT-guided puncture method according to claim 14, characterized in that: In step 8), if the X-ray source hardware does not support pulse exposure, a relatively large mA modulation may be used instead of pulse exposure to significantly reduce the dose.

17. The rapid low-dose CT-guided puncture method according to claim 14, characterized in that: The algorithm and processing flow of the method are verified by numerical simulation, which uses two-dimensional data, but the method itself is not limited to two-dimensional data.

18. A three-source computer tomography system configured to perform the guided puncture method according to any one of claims 1 to 12 or the fast low-dose CT-guided puncture method according to any one of claims 13 to 17.

Images